Key takeaways
- E-filed returns need no separate attachments for most clients.
- Paper returns attach Form W-2 and Form 1099-R with federal withholding, and Form 2441 when the child and dependent care credit is claimed.
- Form 8453 never carries Forms W-2, W-2G or 1099-R.
- Keep records 3 years from filing by default, 6 years when large income is omitted, 7 years for bad debt or worthless securities, and indefinitely when no return was filed.
Most e-filed returns need no attachments
An e-filed return is sent to the IRS as electronic data, with the forms the software builds, so there is nothing to mail.
The exception is a paper item the IRS still needs and cannot receive electronically. For an e-filed return, that item goes on Form 8453, the transmittal for IRS e-file returns, and the form carries only the items listed on its front.
Decision rule: if the return is e-filed and the document is not listed on Form 8453, do not send it. Put it in the client file and keep it for the period in the retention section below.
Paper returns: Form W-2 and Form 1099-R
The 2025 Form 1040 instructions tell the filer to attach Form W-2 to the return when federal income tax was withheld. They also tell the filer to attach Form 1099-R to the front of the return when federal income tax was withheld.
Those are the two wage and retirement forms the instructions single out for attachment. Attach the forms exactly as the instructions name them, then check that the withholding on each form matches the amount reported on the return.
These instructions are for tax year 2025. The 2026 Form 1040 instructions were not read for this guide, so confirm the wording against them before the 2027 season starts.
Statements the return asks for
Some lines on Form 1040 call for a statement rather than a form. Line 16 is one: the 2025 instructions say to attach a statement showing how you figured the tax.
Write the statement with the form and line number, each amount used, the calculation and the reason for the number. A reviewer should be able to rebuild the figure from the statement alone.
Keep a copy of every statement in the client file.
Form 2441 for the child and dependent care credit
Form 2441 is the attachment that a specific credit requires. The IRS says to complete Form 2441, Child and Dependent Care Expenses, and attach it to your federal income tax return to claim the Child and Dependent Care Credit.
Decision rule: if the client paid someone to care for a dependent so the client could work or look for work, ask for the provider's name, address and taxpayer identification number before you finish Form 2441. Without the provider information, the form cannot be completed as written.
Failure mode: a paper return is mailed with the credit claimed but no Form 2441 behind it. Fix it before mailing by attaching the form. If the return has already gone out, tell the client in writing that the form was missing and agree on the correction with the client before anything else is sent.
Form 8949 and Schedule D are built, not mailed separately
Form 8949 is the transaction schedule that feeds Schedule D. The 2025 Schedule D instructions say to complete Form 8949 before you complete line 1b, 2, 3, 8b, 9, or 10 of Schedule D, so the Form 8949 totals come first.
Work from the broker's Form 1099-B. Fill each row from the sale date, the proceeds and the basis the broker reported, and check the box that matches how that basis was reported.
The broker statement is support, so it stays in the file.
Form 8453 and the limits of the e-file route
The IRS says Form 8453 is used solely to transmit the forms listed on the front of the form. A document that is not on the front has no route through the e-file transmittal.
The IRS says do not send Forms W-2, W-2G or 1099-R with Form 8453. A common mistake is adding the client's W-2 to the Form 8453 package because the client expects to see it sent. Pull it out and keep the copy in the file.
The current revision is the 2026 Form 8453, titled U.S. Individual Income Tax Transmittal for an IRS e-file Return. Check the list against the revision for the year you are filing.
Form 8879 is kept, not sent
Form 8879 is the signature authorization for an e-filed return. The IRS FAQ for the e-file signature authorization says the ERO must keep a tamper-proof record in a secure, access-controlled storage system for 3 years from the due date of the return or 3 years from the IRS return receipt date, whichever is later.
For a 2026 return the due date is April 15, 2027, so the earliest the signed form can be discarded is April 15, 2030. If the IRS received the return after the due date, the clock runs from the receipt date instead, and the retention runs later.
Record the destruction date in the document system when the return is filed.
Retention periods for tax year 2026 records
Keep the return and its support for 3 years from the date the return was filed. The IRS says this is generally the period to assess tax you owe, and it applies unless one of the longer rules below applies.
Keep records for 6 years when income that should be reported was left out and the omitted amount is more than 25% of the gross income shown on the return.
Keep records for 7 years when the return includes a claim for a loss from worthless securities or a bad debt deduction. Keep records indefinitely when no return was filed or a fraudulent return was filed.
Keep employment tax records for at least 4 years after the date the tax becomes due or is paid, whichever is later. Keep records relating to property until the period of limitations expires for the year you dispose of the property, because depreciation and gain or loss depend on them.
Worked example: a 2026 return filed on April 15, 2027 with no bad debt claim can be discarded after April 15, 2030. The same return with a bad debt claim has to be kept until April 15, 2034.
State returns follow their own attachment rules
State attachment rules are separate from the federal rules. Some states ask for a copy of Form W-2 when state income tax was withheld, and each state's instructions name the form and where it goes.
Decision rule: if the client's state return shows state tax withheld, check that state's instructions for the attachment before you assemble the state return. Do not assume the federal rule carries over.
What to ask the client for
Send this when you request the wage and retirement forms, word for word: "Please send a copy of every Form W-2 and every Form 1099-R that shows federal income tax withheld for 2026. We attach these to a paper return and keep them in your file for an e-filed return." Then ask the client to confirm that no form is missing.
Send this when the client sold investments, word for word: "Please send the Form 1099-B from each brokerage account for 2026, including the cost basis and sale dates. We need them to complete Form 8949." The request is complete when the client has replied for every account.
Decision rule: if the client paid for child or dependent care, ask for the provider's name, address and taxpayer identification number, and the amount paid. Also ask the client to keep the receipts, because the IRS says records that support a credit must be kept until the period of limitations expires.
Failure modes and fixes
Failure: the client's W-2 went into the Form 8453 package. Fix: remove it, confirm the transmission route with the software, and keep the paper copy in the client file.
Failure: a bad debt was claimed and the workpapers were destroyed after 3 years. Fix: flag any return with a bad debt or worthless securities claim for a 7-year retention period when the return is filed.
Failure: the signed Form 8879 was discarded when the client's return was accepted. Fix: the ERO keeps the signed form for 3 years from the later of the due date or the IRS receipt date, so the clock is not tied to the day the client sees the return accepted.