To sign your tax return, print and sign your name in ink on the signature line at the bottom of page 2 of Form 1040 if you’re filing on paper, or enter a five-digit Self-Select PIN if you’re e-filing your own return. If a paid preparer is e-filing for you, you sign Form 8879 instead, which authorizes them to submit the return on your behalf. Learning how to sign your tax return matters because an unsigned return is not a valid return: the IRS will not process it or release your refund until the signature is on file.1Internal Revenue Service. Quality Review of the Tax Return – Section: Taxpayer Signature
Whichever method you use, your signature is a sworn declaration. The jurat printed above the signature line reads: “Under penalties of perjury, I declare that I have examined this return and accompanying schedules and statements, and to the best of my knowledge and belief, they are true, correct, and complete.”2Internal Revenue Service. Form 1040 – US Individual Income Tax Return Review the numbers before signing, even if someone else prepared the return. A preparer’s signature does not shift responsibility away from you.3Internal Revenue Service. VITA/TCE Volunteer Resource Guide – Return Signature
Signing a Paper Form 1040
The signature area sits at the bottom of the second page of Form 1040. The perjury declaration is printed above two signature lines: one for you and one for a spouse if you’re filing jointly. Sign in ink on the line labeled for the taxpayer and enter the date next to your signature.1Internal Revenue Service. Quality Review of the Tax Return – Section: Taxpayer Signature
Below your signature area is the “Paid Preparer Use Only” section. If a professional prepared the return, they sign there and enter their firm information and PTIN. The preparer is supposed to sign after completing the return but before handing it to you for your signature.4Internal Revenue Service. Notice 2008-12 – Preparer Signature Requirements Under Section 6695(b) If a paid preparer refuses to sign or won’t provide a PTIN, treat it as a warning sign and find someone else.5Internal Revenue Service. Topic no. 254, How to Choose a Tax Return Preparer
Signing an E-Filed Return You Prepared Yourself
Electronic returns don’t use ink. Instead, tax software walks you through the Self-Select PIN method, which is the IRS’s approved electronic signature for self-prepared returns. You choose any five digits except all zeros, and that PIN acts as your legal signature on the return.6Internal Revenue Service. Topic no. 255, Signing Your Return Electronically
The PIN alone isn’t what proves you’re you. The identity check happens through two additional pieces of information: your date of birth and either your prior-year adjusted gross income (AGI) or your prior-year Self-Select PIN. If you have an Identity Protection PIN, that replaces the AGI verification step.7Internal Revenue Service. Validating Your Electronically Filed Tax Return
A common snag is an AGI that doesn’t match IRS records. This often happens if you amended last year’s return, or if you filed late and the IRS hasn’t finished processing it. If the software rejects your submission, correct the AGI and resubmit. You can usually fix rejection issues and refile without penalty as long as you do so before the filing deadline.
Signing an E-Filed Return Your Preparer Submits
When a tax professional e-files for you, they typically use the Practitioner PIN method. You don’t have to provide your prior-year AGI under this approach. Instead, you sign Form 8879, IRS e-file Signature Authorization, which gives the preparer legal consent to transmit the return.6Internal Revenue Service. Topic no. 255, Signing Your Return Electronically8Internal Revenue Service. About Form 8879, IRS e-file Signature Authorization
Read Form 8879 before signing. It shows your return type, adjusted gross income, total tax, and refund or balance due, which lets you confirm the preparer entered the key numbers correctly. You don’t mail 8879 to the IRS. The preparer keeps it in their records, but your signature on that form is what legally authorizes the filing.9Internal Revenue Service. Form 8879 – IRS e-file Signature Authorization
Joint Returns Need Both Signatures
On a joint return, both spouses must sign, whether the return is on paper or electronic.1Internal Revenue Service. Quality Review of the Tax Return – Section: Taxpayer Signature For a paper return, each spouse signs and dates their own line. For an e-filed return, each spouse enters their own five-digit PIN.6Internal Revenue Service. Topic no. 255, Signing Your Return Electronically
Understand what you’re signing. A joint return makes both spouses responsible for the full tax owed, not just their share, and that liability continues even after divorce.10Office of the Law Revision Counsel. 26 USC 6013 – Joint Returns of Income Tax by Husband and Wife If your spouse understated tax and you didn’t know, innocent spouse relief exists as a later remedy through Form 8857, but the signature itself commits you to the whole bill.11Internal Revenue Service. Innocent Spouse Relief
When Someone Else Can Sign for You
Having a family member or agent sign your return is more restricted than most people expect. Federal regulations permit another person to sign your income tax return only in three situations: you can’t sign because of disease or injury, you’ve been continuously outside the United States for at least 60 days before the filing deadline, or the IRS grants specific permission for another good cause. A general power of attorney doesn’t cover it. The authority has to be granted specifically on Form 2848, and the form must state which of those three reasons applies.12Internal Revenue Service. Instructions for Form 2848 – Power of Attorney and Declaration of Representative
For a deceased taxpayer’s final return, a surviving spouse filing jointly signs and writes “Filing as surviving spouse” in the signature area if no personal representative has been appointed. If one has been appointed, both the surviving spouse and the representative sign. You can’t file a joint return with a deceased spouse if you remarried before the end of the year your spouse died.13Internal Revenue Service. Signing the Return
Identity Protection PIN Is Separate
If the IRS has issued you an Identity Protection PIN (IP PIN), you must include it on every federal return you file, including prior-year returns. It’s a six-digit number, separate from the five-digit Self-Select PIN used to sign an e-filed return. The IP PIN is a security check that confirms your identity before the IRS accepts any return bearing your SSN.14Internal Revenue Service. Get an Identity Protection PIN (IP PIN)
A new IP PIN is generated each January and is valid only for that calendar year. Getting it wrong or leaving it off will cause an e-filed return to be rejected or a paper return to be delayed. The program is open to anyone with an SSN or ITIN, and you can enroll online through your IRS account with ID.me verification, by Form 15227 if your income is below the applicable threshold, or in person at a Taxpayer Assistance Center.15Taxpayer Advocate Service. Get an IP PIN to Protect Yourself From Tax-Related Identity Theft
What Happens If You Forget to Sign
An unsigned return is not valid and won’t be processed until the signature is on file.1Internal Revenue Service. Quality Review of the Tax Return – Section: Taxpayer Signature For a paper return, the IRS typically sends a Letter 12C asking for the missing signature. You have 20 days from the date of the letter to respond, and your refund generally arrives six to eight weeks after the IRS receives your reply.16Internal Revenue Service. Understanding Your Letter 12C
For an e-filed return, the software usually won’t submit without the electronic signature step, so a missing signature is rare. Rejections instead tend to come from a wrong AGI or a missing IP PIN. Fix the issue and resubmit before the deadline to avoid penalty.
Ignoring a Letter 12C is worse than filing late. The IRS treats a return that never received a valid signature as if it was never filed, which can trigger late-filing penalties and can leave the audit window open indefinitely, because the statute of limitations only starts running once a valid return is filed. Sign what they ask for and send it back promptly.