ITR Filing Documents Checklist: Form 16, TDS Certificates, AIS and Everything Else

Do not open the filing portal first. Open a folder first. Almost every painful ITR season I see begins the same way: the taxpayer logs in, starts answering questions, and then goes hunting for a document that is sitting in some other email account, some other phone, or an HR portal whose password expired in March. The return itself takes an hour or two. The hunting takes the weekend.

So here is the whole pile, gathered in one place, for Assessment Year 2026-27 — the return for income earned between 1 April 2025 and 31 March 2026, filed under the Income-tax Act, 1961. This is the checklist behind the what you need before you start section of our filing service page, set out in full. Nothing on this list needs to be uploaded with the return, point to note. These papers are for you — and for whoever prepares your return — so that every figure you type can be traced back to a document.

Start with the three statements the department already holds

Three documents sit at the top of the pile, and they are not interchangeable. Each one answers a different question.

Download all three before you file, not during. Form 26AS and the AIS both sit inside your account on incometax.gov.in. Changed jobs during the year? Then you need a Form 16 from each employer, for the months each one paid you. One employer, one certificate. Two employers, two certificates — and the second employer rarely knows what the first one paid, which is exactly how salary gets under-reported or taxed twice at the wrong slab.

For TDS on anything other than salary — bank interest, rent, professional fees, commission — the certificate is Form 16A, issued by the deductor for each quarter. Collect those too. And if the three statements disagree with each other, stop. That is a separate job with its own fix, and we have set it out in our guide to fixing an AIS, 26AS and Form 16 mismatch before you file. File on reconciled numbers. Never on hope.

Identity, access and the bank account your refund will land in

• PAN and Aadhaar. Your PAN is your login ID on the portal. Keep Aadhaar beside it — you will need the mobile number registered with Aadhaar if you plan to e-verify with an OTP, and your PAN and Aadhaar should be linked.
• Portal access. Your incometax.gov.in password, tested a day early. Password resets on deadline morning are a special kind of misery.
• Bank details. Account number and IFSC for every account you hold, and the refund account pre-validated on the portal with EVC enabled. A refund sent to a closed or unvalidated account does not arrive, and the reissue queue is slow.
• Last year's return. The acknowledgement and computation, mainly for brought-forward losses. A capital loss or business loss claimed last year has to travel into this year's return correctly, or it quietly dies.

Income papers, head by head

Salary. Form 16 from every employer, plus salary slips for any month the certificate seems to skip. If an employer deducted no tax — income below the deduction threshold, say — it may not issue a Form 16 at all. Ask for a salary statement instead, and keep the slips. The income is still yours to report.

House property. Rent receipts or the rent agreement for rent you received, and your tenant's details where TDS was deducted on rent. For rent you paid and want to claim as HRA: receipts, the agreement, and your landlord's PAN where the year's rent crosses ₹1,00,000 — your employer will ask for it with your investment declaration, and a claim without it invites questions. For a home loan, get the lender's interest certificate for the year. It splits principal and interest for you, which is what the return needs: interest under the house property head, principal inside Section 80C.

Capital gains. The broker's profit and loss statement and capital gains report for shares and mutual funds, contract notes for large trades, and your mutual fund capital gains statement across registrars. Sold a property? The sale deed, the purchase deed, and receipts for any improvement and transfer expenses. The AIS reports sale consideration. It does not know your cost. Your papers are what stand between the two figures.

Business or profession. Your books for the year — profit and loss account, balance sheet, bank statements for the business accounts — and your GST returns, if you are registered, so turnover in the two systems can be tied together. Freelancers and consultants: keep the Form 16A certificates from clients who deducted tax, and the invoices behind them.

Other sources. Interest certificates from every bank and post office account, including the dormant one and the one you closed in October. Dividend statements from your demat account. Family pension papers, if that applies. Small interest is still interest. The bank has already reported it.

Deduction proofs — and why the regime decides how much they matter

The new regime under Section 115BAC is the default. That one line changes how hard you need to work at this section.

Filing under the new regime? Most Chapter VI-A deductions simply do not apply, and the proof hunt shrinks. Filing under the old regime — or still deciding — gather the full set: Section 80C proofs (EPF statements, PPF passbook, ELSS and LIC statements, tuition fees, housing loan principal), Section 80D health insurance premium receipts for yourself and your parents, NPS contribution receipts, education loan interest certificates, and donation receipts with the donee's PAN and registration details.

One warning, because it catches people every season. If you have business or professional income and you want the old regime, the choice is not a tick-box in the return. You must file Form 10-IEA on or before your Section 139(1) due date. Miss that, and the default regime applies to you for the year whatever your proofs say. Salaried taxpayers with no business income choose inside the return itself. Different doors. Know which one is yours before the due date, not after.

Still weighing the two? Pick the right ITR form for your income first, because the form follows the income — file in the wrong one and the return can come back defective under Section 139(9). Then run both regime computations on your actual numbers. Gut feeling is a poor tax planner.

Tax already paid: the challans

Advance tax and self-assessment tax challans for the year — the BSR code, challan serial number, date and amount. These payments should already sit in your Form 26AS. Should. Where a challan is missing from 26AS, the paper challan is your proof and your correction route starts with the bank. Claim credit only for what you can show. A credit claimed without a matching entry is a demand waiting for a date.

Think of the pile this way

Your documents are the pieces of a jigsaw, and the department already has the picture printed on the box lid — that picture is your AIS. Filing well is nothing more grand than this: your completed picture and their lid should show the same year. Every paper on this checklist is a piece. The missing piece never stays hidden; it just gets found later, by CPC, at a worse moment and in a colder letter.

When a paper simply does not exist

It happens. An ex-employer has shut down. A bank has merged. A deductor never issued Form 16A. Do not stall the return over one missing certificate, and do not guess the figure either. Use the statement that governs that fact: tax credit is proved by Form 26AS, income by your bank credits and contracts, and write to the deductor or bank in the meantime — an email with figures, not a phone call. Keep that trail with the return papers. If a question comes two years later, the trail is the answer.

Gather the pile a week before you intend to file, tick it off in one sitting, and the filing itself becomes the easy part. If you would rather hand the pile to someone who reconciles these statements for a living, our income tax return filing team will work through your Form 16, 26AS and AIS line by line, compute both regimes on your numbers, and file a return where every figure traces back to a paper you actually hold.