To file a paper tax return, download or order the correct IRS forms, fill them out and sign them, assemble the pages in the order the IRS specifies, and mail the package to the processing center assigned to your state. For most individual returns covering the 2025 tax year, the deadline is April 15, 2026.1Internal Revenue Service. IRS Announces First Day of 2026 Filing Season The steps below walk through each piece of the process.
Get the Forms
Every current-year form, schedule, and instruction booklet is available as a free download at irs.gov.2Internal Revenue Service. Downloading and Printing The IRS publishes these as fillable PDFs, so you can type your entries on screen before printing. That produces a much cleaner return than handwriting.
If you’d rather have printed forms mailed to you, call the IRS forms line at 800-829-3676.3Internal Revenue Service. Tax Forms and Publications IRS Taxpayer Assistance Centers and many public libraries also stock forms during filing season, though supplies thin out as April approaches.
Fill Out Your Return
Before you start writing, gather every income document for the tax year: W-2s from employers, 1099s for freelance income, interest, dividends, and retirement distributions, and any statements you’ll need for deductions or credits. Having everything in front of you prevents the kind of errors that get returns kicked back.
If you’re handwriting entries instead of typing them into the fillable PDF, use dark ink and print clearly. The IRS scans paper returns into its system, and smudged or illegible entries slow processing or trigger manual review.
Sign and date the return. An unsigned Form 1040 is treated as incomplete and will be returned to you, costing weeks.4Internal Revenue Service. About Form 1040, U.S. Individual Income Tax Return If you’re filing jointly, both spouses must sign. Special rules apply when a spouse can’t sign due to illness, absence, or death, but the default is two signatures.
Assemble the Pages in Order
The IRS expects a specific stacking sequence when you mail a paper return:
- Staple copies of your W-2s, W-2Gs, and any 1099-Rs that show tax withheld to the front of Form 1040, in the area indicated on the form.
- Behind Form 1040, arrange schedules and additional forms in the order of their Attachment Sequence Number, printed in the upper-right corner of each page.
- Place any supplemental statements or explanations behind the schedule they relate to, in the same order.
Getting the order wrong won’t invalidate the return, but a disorganized stack increases the odds of processing errors or delays. Keep a complete copy of everything you send for your own records.
Send a Payment With the Return
If your return shows a balance due, mail your payment with it. Make the check or money order payable to “United States Treasury,” not “IRS.” Never send cash.5Internal Revenue Service. Pay by Check or Money Order On the check, write:
- Your name and address
- Daytime phone number
- Social Security number or ITIN
- The tax year the payment covers
- “Form 1040”
Include Form 1040-V, the payment voucher, in the envelope. Don’t staple or paper-clip the payment or voucher to the return; place them loose in the envelope.6IRS. 2025 Form 1040-V Payment Voucher for Individuals Stapled payments slow processing and can damage the check during automated handling.
If you can’t pay the full amount, file the return on time anyway and pay what you can. You can request an installment agreement by mailing Form 9465 or by calling the IRS at 800-829-1040 after your return is processed.7Internal Revenue Service. Payment Plans – Installment Agreements Filing on time with a partial payment is far cheaper than not filing.
Find the Right Mailing Address
There is no single IRS mailing address. The correct one depends on your state and on whether you’re enclosing a payment. Look up your address on the IRS’s “Where to File” chart before sealing the envelope.8Internal Revenue Service. Where to File Addresses for Taxpayers and Tax Professionals Filing Form 1040 or Form 1040-SR Using last year’s address is risky; the IRS occasionally reassigns states to different centers. The wrong address won’t void your return, but it routes through an extra processing center and adds weeks.
Use a sturdy envelope large enough that you don’t have to fold the pages. Folded returns are harder for the IRS’s scanning equipment to process. Weigh the envelope; a multi-page return with attachments usually exceeds one ounce and needs extra postage. As of January 2026, USPS charges more for a thick return mailed as a flat than for a standard letter.
If you’d rather use a private carrier, the IRS designates specific FedEx, UPS, and DHL Express services that qualify for the same timely-filing protection as USPS.9Internal Revenue Service. Private Delivery Services (PDS) Only named services (like FedEx Priority Overnight, UPS Next Day Air, and DHL Express Worldwide) count. Standard ground shipping doesn’t. Private carriers also require a street address rather than a P.O. box, and the IRS publishes three street addresses for this purpose in Austin, Kansas City, and Ogden.10Internal Revenue Service. Submission Processing Center Street Addresses for Private Delivery Service (PDS) The same street address applies whether or not you’re enclosing a payment.
Prove You Mailed on Time
Your filing date is the date you drop the return in the mail, not the date the IRS opens the envelope. Under federal law, a USPS postmark on or before the deadline counts as timely filed even if the IRS receives it days or weeks later.11Office of the Law Revision Counsel. 26 U.S. Code 7502 – Timely Mailing Treated as Timely Filing and Paying The same rule applies to IRS-designated private delivery services.
You need proof, though. If the IRS ever claims it never received your return or says it arrived late, you’ll want documentation showing when you mailed it. USPS Certified Mail with a return receipt gives you a stamped counter receipt plus a signed confirmation when the IRS receives the envelope. As of 2026, the extra cost is $5.30 for certification and $4.40 for the return receipt, or $9.70 on top of postage. A Certificate of Mailing costs less and provides a postmark and date without tracking.
File an Extension by Mail if You Need More Time
If you won’t be ready by April 15, mail Form 4868 before the deadline to get an automatic six-month extension. That pushes your filing date to October 15, 2026, for most calendar-year filers. An extension gives you more time to file, not more time to pay. Any tax owed is still due April 15, and interest and penalties accrue on unpaid balances after that date.
Form 4868 has its own mailing addresses, separate from Form 1040. Look them up on the IRS “Where to File” page for Form 4868.12Internal Revenue Service. Where to File Addresses for Businesses and Tax Professionals Filing Form 4868 If you’re sending a payment with the extension, use the payment address listed for your state. Certified mail protects you here too.
What Happens if You’re Late
Missing the deadline without an extension triggers two separate penalties that can stack. The failure-to-file penalty is 5% of unpaid tax for each month or partial month the return is late, capped at 25%.13Internal Revenue Service. Failure to File Penalty The failure-to-pay penalty is a much smaller 0.5% per month on unpaid tax, also capped at 25%.14Internal Revenue Service. Topic No. 653, IRS Notices and Bills, Penalties and Interest Charges
The practical takeaway: file on time even if you can’t pay. A return filed on time with no payment costs 0.5% per month on the balance. A return filed five months late with no payment costs 25% plus ongoing interest. Form 4868 is free and eliminates the failure-to-file penalty entirely.
How Long Processing Takes
Paper returns take significantly longer than e-filed returns. Electronic returns are generally handled within 21 days. Paper returns require manual handling, scanning, and data entry, and the IRS advises paper filers to wait at least four weeks after mailing before checking on a refund.15Internal Revenue Service. Refunds IRS representatives can’t research the status of a paper return until six weeks have passed.16Internal Revenue Service. Why It May Take Longer Than 21 Days for Some Taxpayers to Receive Their Federal Refund Returns with errors, missing information, or review flags can stretch to several months.
Track your refund using the IRS “Where’s My Refund?” tool at irs.gov. You’ll need your Social Security number, filing status, and exact refund amount.15Internal Revenue Service. Refunds Don’t panic if the tool shows nothing for the first few weeks; paper returns take longer to appear in the system.
If more than six weeks have passed and neither the online tool nor an IRS representative can locate your return, you may need to file a second one. Before doing that, confirm you used the correct address and that your certified mail receipt, if you have one, shows delivery. The Taxpayer Advocate Service can help if your return appears to be genuinely lost in the system.17Taxpayer Advocate Service – IRS. I Don’t Have My Refund