Updated October 18, 2026. Quick answer: Part II is where you tell the IRS why you are filing Form 1040-X, and the form says you must complete it. Part III is the direct deposit section for e-filed amended returns only, using lines 31 through 33 for one account. Both follow the numbered lines and the dependents section.
Read box by box from the IRS form text: Form W-2c Notice to Employee.
Part II: the explanation of changes
The form says “tell us why you are filing Form 1040-X. You must complete Part II.” The instructions put it this way: “The IRS needs to know why you are filing Form 1040-X.” Their examples include that you:
- “Received another Form W-2 after you filed your return”
- “Forgot to claim the child tax credit or the credit for other dependents”
- “Changed your filing status from qualifying surviving spouse to head of household”
For the column B changes, the instructions say “Explain each change in Part II. If you need more space, attach a statement.” “Attach any schedule or form relating to the change.” The form’s header repeats the point: “Attach any supporting documents and new or changed forms and schedules and complete Part II.”
Part III: direct deposit
The part applies to e-filed returns. The instructions say “Beginning in February 2023, if you electronically file a Form 1040-X for tax year 2021 or later, you may request your refund be directly deposited into your checking or savings account.” The request covers “If you want us to directly deposit the amount shown on line 22 to your checking or savings account at a bank or other financial institution (such as a credit union) in the United States:”
- “Complete lines 31 through 33 on Form 1040-X (if you want your refund deposited to only one account); or”
- “Check the box on Form 1040, 1040-SR, or 1040-NR, line 35a, and attach Form 8888, Allocation of Refund, if you want to split the direct deposit into more than one account.”
The instructions add “The account must be in your name.” They say “A direct deposit will be issued using the banking information on Form 1040-X.” and “Do not complete lines 35b through 35d on Form 1040, 1040-SR, or 1040-NR.” If a deposit cannot be made, “If an account issue prevents a direct deposit, a refund will be issued by paper check to the most recent address.”
Where the number comes from
Part II has no amounts. It is your own explanation of each change you made in column B, written for the return year you are amending. The Part III account details are the routing and account information for your own bank account, entered on lines 31 through 33. The refund the deposit refers to is line 22, explained on the lines 18 to 23 page.
Where it goes next
After Part III the form moves to signing. The instructions say “Form 1040-X isn’t considered a valid return unless you sign it in accordance with the requirements in these instructions.” The signing rules are outside the lines covered on this page. The earlier sections are on the lines 12 to 17, lines 18 to 23 and lines 24 to 30 pages.
Edition and line numbers
This page reads the December 2025 revision of Form 1040-X and its December 2025 instructions, the current files irs.gov served on 2026-10-18. The form is marked “(Rev. December 2025)” and it amends the return year the filer enters at the top, so the revision date is not the same thing as the year being amended. The form’s own instruction at the top says “Attach a completed Form 1040, 1040-SR, or 1040-NR, with your changes, for the return year entered below”. Check the revision date printed on the form you are filling in and the return year you are amending, and use the line numbers on that revision, because a different revision can number or word its lines differently. The whole form is walked through on the Form 1040-X walkthrough page.
Common mistakes
- Leaving Part II blank. The form says “You must complete Part II.”
- Asking for a split deposit on lines 31 to 33. Those lines are for one account; the instructions say “Check the box on Form 1040, 1040-SR, or 1040-NR, line 35a, and attach Form 8888, Allocation of Refund, if you want to split the direct deposit into more than one account.”
- Using an account that is not yours. The instructions say “The account must be in your name.”
Related: Form 1040 lines 34 to 36, Form 1040 line by line, Form 1040, and Form 1040 line 37.
Sources
- Instructions for Form 1040-X, Amended U.S. Individual Income Tax Return (Rev. December 2025): https://www.irs.gov/pub/irs-pdf/i1040x.pdf
- Form 1040-X, Amended U.S. Individual Income Tax Return (Rev. December 2025): https://www.irs.gov/pub/irs-pdf/f1040x.pdf
Read from the IRS documents linked above on October 18, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer, the account provider or the IRS is the right place to confirm anything consequential.