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Tax Preparation Engagement Letter: What to Include

9/21/2026

Most disputes between tax preparers and clients are not about whether the return was right. They are about what the client thought the firm was going to do. The client assumed the fee covered the IRS letter that arrived in August. The client assumed the firm would notice the foreign account nobody mentioned. The client assumed "do my taxes" included last year's amended return and the LLC that started in October.

A tax preparation engagement letter exists to close that gap before the work starts. It is the document that defines scope, assigns responsibility, sets the fee terms and records the authorizations the return process needs. This post covers what a letter for tax return preparation should contain, section by section, and where the federal rules shape what it can say.

This is practice guidance, not legal advice. Engagement letters are contracts, and state law governs things like limitation of liability, dispute resolution and fee collection. Have your firm's template reviewed by counsel and, where you carry one, your professional liability insurer.

Why a Separate Letter for Tax Returns

Firms that do bookkeeping, advisory and tax work often use one general engagement letter. That is a mistake for return preparation, for three reasons.

Return preparation is an annual engagement with a defined deliverable. A bookkeeping engagement is ongoing. A return engagement starts, produces a filed return and ends. The letter should match that shape, including when the engagement ends and what happens to post-filing work.

Return preparation carries federal requirements the other services do not. E-file signature authorization, Section 7216 consents for use or disclosure of return information, and paid-preparer due diligence obligations all live inside the return engagement.

The scope boundary is where the risk is. The most common liability claims against preparers involve something the client believed was included. A tax-specific letter can list the exclusions that matter for returns, which a general letter cannot do well.

Professional standards generally treat a written understanding with the client as best practice rather than a universal legal requirement, and many insurers expect one. Whatever the standard that applies to your firm, the practical answer is the same: no signed letter, no work.

The Core Sections of a Tax Return Engagement Letter

1. Parties and tax year

State exactly who the client is. For a married couple filing jointly, both spouses are clients and both should sign. If the firm prepares returns for dependents in the same household, each one is a separate engagement or should be named separately. State the tax year covered. A letter that says "your tax return" without a year will be read by the client as "every return, forever."

2. Scope of services

List the returns the firm will prepare, by form. For an individual client that typically means the federal Form 1040 and named state and local returns. If the firm will prepare estimated tax vouchers for the following year, say so. If it will prepare an extension, say so and say what the extension does and does not do.

Be specific about states. A client who moved mid-year or works across a state line may need part-year or nonresident returns in a second state. If the letter names only the home state, the second state is outside scope until the client tells you about it and the letter is amended.

3. What is not included

This is the section that prevents disputes. List the services the fee does not cover, even if the firm offers them separately. Common exclusions for individual returns:

  • Responding to IRS or state notices, examinations or appeals after filing
  • Amended returns for this or prior years
  • Prior-year returns not yet filed
  • Tax planning or projections beyond what is incidental to preparing the return
  • Business entity returns, trust returns and gift tax returns
  • Foreign financial account reporting and other international information returns
  • Bookkeeping, reconstruction of records or payroll filings
  • Review or verification of the client's records

The exclusions list is not about refusing work. It is about pricing work. When the IRS letter arrives, a client who signed a letter saying notice responses are billed separately expects an invoice. A client who signed a letter that said nothing expects it free.

4. Client responsibilities

The client is responsible for the completeness and accuracy of the information provided, for keeping the records that substantiate income, deductions and credits, and for the final content of the return they sign. The letter should say so plainly.

Spell out the specific items clients most often fail to disclose, so the omission is the client's and the request is on record:

  • All income, including income without an information return, cash income and digital asset transactions
  • Foreign bank and financial accounts, foreign assets and foreign income
  • Changes in marital status, dependents, address or residency
  • Notices received from any taxing authority during the year
  • Estimated tax payments made, with dates and amounts

If the firm will claim credits or filing status covered by the paid-preparer due diligence rules (the earned income credit, the child-related credits, the American opportunity credit or head of household status), say that the firm is required to ask questions and may need supporting documents, and that the IRS may ask the client for documentation later. That sets the expectation before the questions start.

5. The firm's responsibilities and limits

State what the firm will do: prepare the returns from the information provided, apply current law, and resolve questionable items in a manner consistent with professional standards. State what it will not do: audit or verify the client's records, or detect fraud, theft or errors in the client's books.

State how the firm handles positions where the law is unclear, and that the client will be told about positions that carry meaningful risk, including disclosure positions. This protects both sides. The client makes an informed decision, and the firm has a record that the decision was the client's.

6. Electronic filing and signature authorization

For e-filed individual returns, the taxpayer signs either by self-selected PIN or by authorizing the electronic return originator to enter the PIN using Form 8879, IRS e-file Signature Authorization. IRS Publication 1345 requires the taxpayer to sign and date Form 8879 before the ERO originates the electronic submission, and the ERO to keep Forms 8879 and 8878 for three years from the return due date or the IRS received date, whichever is later. The forms are not sent to the IRS unless requested.

The engagement letter should say the return will not be filed until the signed authorization is received, and that the client is responsible for reviewing the return before signing. It should also say that the firm will confirm acceptance and tell the client if the return is rejected.

Preparers who reasonably expect to file 11 or more covered returns in a calendar year are generally required to e-file them under section 6011(e)(3). A client who wants to paper-file may do so, but the preparer keeps a signed taxpayer choice statement and attaches Form 8948 to the paper return. If your firm accommodates paper filing, say in the letter how that request is made.

7. Section 7216 consents: separate documents

Section 7216 and its regulations restrict how preparers use and disclose tax return information. Many ordinary uses within return preparation do not need consent. Uses beyond that, such as using return information to offer non-tax services, and disclosures to third parties, generally do.

The key structural rules from Treasury Regulations section 301.7216-3:

  • Consent must be obtained before the use or disclosure.
  • For Form 1040-series filers, one document cannot authorize both a use and a disclosure. Uses and disclosures need separate written consents.
  • A consent that does not state a duration lasts one year from the date it is signed.
  • Conditioning services on consent makes it involuntary, with a limited exception for disclosures between preparers assisting with the return.
  • Social Security numbers carry extra restrictions when return information is disclosed to a preparer located outside the United States.

Rev. Proc. 2013-14 sets out the required format and mandatory statements for consents by Form 1040 filers. Because of these rules, keep 7216 consents out of the body of the engagement letter. Attach them as separate documents, signed separately, so a client can sign the engagement letter without consenting. If your firm uses offshore staff or third-party processing, this is the section your attorney should look at hardest.

8. Authorizations and representation

Preparing a return is not representing the client before the IRS. If the client wants the firm to receive notices or speak to the IRS, that needs a separate authorization, typically Form 2848 for representation or Form 8821 for information only. The letter should say these are separate and are not created by the engagement.

The return itself has a third-party designee checkbox that lets the IRS discuss that return with a named person for a limited period. State whether the firm will be named and what that permits. Clients regularly think checking that box means the firm will handle anything that arrives.

9. Fees and billing

State the fee basis: a fixed fee, a fee schedule by form and complexity, or hourly rates. Say what triggers additional fees, such as late or incomplete information, additional forms, or scope changes. State when fees are due, whether a retainer is required, and what happens if invoices are not paid, including whether the firm will hold the filing of the return.

Two federal rules limit what this section can say. Circular 230 section 10.27 restricts contingent fees for matters before the IRS, so do not tie the preparation fee to the size of the refund without reviewing that section first. And Circular 230 section 10.28 requires a practitioner, at the client's request, to promptly return client records needed for the client to comply with federal tax obligations, even during a fee dispute (the practitioner may keep copies). A clause that says the firm will hold the client's original documents until the invoice is paid is a problem. A clause that says the firm may decline to release its own work product until paid may be acceptable, depending on state law. Our post on how to price tax preparation services covers the pricing decisions behind the fee section.

10. Deadlines and information cutoff

State the date by which the client must deliver complete information for the return to be filed by the original due date. State that information received after that date may result in an extension, and that an extension extends the time to file, not the time to pay. Put this in writing every year. Clients forget it every year.

11. Data security and communication

Tax preparers are financial institutions under the Gramm-Leach-Bliley Act and are subject to the FTC Safeguards Rule, which requires a written information security program. The engagement letter is not the place for the whole program, but it should tell the client how documents are to be exchanged (a portal, not email attachments), how the firm will verify identity before discussing the return, and that the client should not send sensitive data by unsecured means. IRS Publication 5708 provides a template for building the written plan itself.

12. Records, termination and dispute resolution

State how long the firm keeps its files and that the client should keep their own copies. State that either party may end the engagement in writing and what is billed if that happens. Any limitation of liability, mediation or arbitration clause, or choice of law clause is a state-law question: have counsel draft it, and confirm your insurer accepts it.

13. Signatures and timing

Both spouses on a joint return sign. The letter is signed and returned before work begins, not with the organizer, not at pickup. Electronic signatures through the firm's portal are common and practical. Record the date the signed letter was received.

Individual Returns vs Business Returns

A 1040 engagement letter and a business return engagement letter overlap but are not interchangeable. Business engagements need to address who at the entity is authorized to act, whether the firm prepares owner K-1s and owner returns under the same engagement, whether payroll and information return filings are in scope, year-end bookkeeping adjustments, and who is responsible for issuing Forms 1099. Use a separate template for each, and for each entity.

Common Mistakes

Mistake

Consequence

Letter sent after work starts

Scope dispute with no signed baseline

One spouse signs a joint engagement

The other spouse is not clearly a party

No exclusions list

Notice responses and amended returns become unpaid work

7216 consent buried in the letter

Consent may be invalid; client cannot decline it separately

Same template for every client and every year

Stale terms, wrong states, missed new entities

No information cutoff date

Every late file becomes an argument about extensions

Holding client documents for unpaid fees

Conflict with Circular 230 section 10.28

 

Using the Letter as a Process Control

The engagement letter also does operational work inside the firm. A signed letter is the first gate in intake: no letter, no organizer processing, no preparer assignment. It sets the information cutoff that drives the season's extension list. It records which states and forms are in scope, so a reviewer can check the return against the letter. And it puts the fee terms in writing before the client has a reason to dispute them. Our post on handling difficult clients during tax season shows how often the root of a difficult client is an unclear engagement.

Update the template every year before the season. Law changes, new forms, the firm's fee schedule and its security procedures all move. Review the template at the post-season debrief, while the year's scope disputes are fresh.

Training Staff on What the Letter Promises

Everyone who talks to clients needs to know what the letter says, because staff make informal promises that contradict it. A preparer who tells a client "don't worry, we'll handle it if the IRS writes" has just expanded the scope. Brief the team on the exclusions and the information cutoff at the start of the season.

Preparers also need the technical grounding to recognize when a client's facts move outside scope: a second state, a new entity, a foreign account, a credit that triggers due diligence. The Advanced I Individual Income Tax Preparation Course is focused on individual return preparation. For the rules on preparer conduct, penalties and data security that shape several of the clauses above, see Tax Practitioner Regulations, Penalties and Security.

Next Steps

Start from your current letter and test it against the sections above: parties and year, scope, exclusions, client responsibilities, firm responsibilities, e-file authorization, separate 7216 consents, representation, fees, information cutoff, data security, termination and signatures. Fix the gaps, have counsel review the result, and send it before the first organizer goes out. For staff who need a firmer footing in individual returns before the season, start with the Advanced I Individual Income Tax Preparation Course, and pair the letter with our individual tax return checklist so intake matches what the letter asks for.

Frequently Asked Questions

Is a tax preparation engagement letter required by law?

Generally no single federal rule requires a written engagement letter for return preparation, and professional standards tend to treat it as best practice rather than a mandate. Some state rules, peer review programs and professional liability insurers expect one. In practice, a signed letter is the firm's main evidence of what it agreed to do and what the client agreed to provide. Without it, a scope dispute becomes one person's memory against another's. Treat it as required in your own procedures: no signed letter, no work. Confirm any state-specific requirements with your board or counsel.

What should a 1040 engagement letter include?

At minimum: who the clients are (both spouses for a joint return), the tax year, the federal, state and local returns in scope, a list of excluded services, the client's responsibility for complete and accurate information and records, the firm's responsibilities and limits, e-file signature authorization terms, fee basis and payment terms, the information cutoff date, how documents are exchanged securely, how the engagement ends, and signatures. Section 7216 consents, if needed, should be separate documents. Representation authority, such as Form 2848, should be addressed separately too, because preparing a return does not make the firm the client's representative.

Can I include Section 7216 consent in the engagement letter?

It is better not to. Under Treasury Regulations section 301.7216-3, consent must be obtained before the use or disclosure, Form 1040 filers need separate documents for uses and for disclosures, and conditioning services on consent generally makes the consent involuntary. Rev. Proc. 2013-14 adds format and mandatory-statement requirements for Form 1040 filers. Embedding consent in the engagement letter makes it hard to show the consent was voluntary and correctly formatted. Use stand-alone consent forms that the client signs separately and can decline without losing the engagement.

Should the engagement letter cover IRS notices and audits?

It should address them, usually by excluding them from the preparation fee and explaining how they are billed. Clients often assume notice responses are included. State that responding to notices, examinations and appeals is a separate service, and that representation requires a separate authorization such as Form 2848. If your firm offers a fixed-fee notice service or a limited response included in the fee, describe exactly what it covers. The goal is that a client who receives an IRS letter already knows what will happen when they forward it to you.

When should the engagement letter be sent and signed?

Before any work begins, and ideally before the client's organizer is processed. Many firms send the letter with or ahead of the organizer and make a signed letter the first intake gate. Both spouses should sign a joint engagement. Electronic signature through a secure portal is common. Send a new letter each year rather than relying on a multi-year letter, because scope, fees, law and the client's circumstances change. Record the date the signed letter was received so the file shows the engagement existed before preparation started.

Can I use an AICPA sample engagement letter?

Professional bodies and insurers publish sample letters, and they are a reasonable starting point if you have access to them. Do not copy one unchanged. Every firm's services, fee structure, data-handling practices and state law differ, and a sample written for one context can promise things your firm does not do. Adapt the scope, exclusions and fee sections to your practice, add your own security and document-exchange procedures, keep 7216 consents separate, and have the finished template reviewed by counsel and your insurer before using it.