The 1040 Client Document Checklist for Tax Preparers (2026)
Every form and record to collect from an individual client before you prepare their 1040 — organized so nothing slips through.
August 30, 2026
Preparing an accurate 1040 starts long before you open your tax software. It starts with getting the right documents from the client — completely, and in one pass. The preparers who lose the most time in February and March are not the ones doing complex returns; they are the ones chasing a missing W-2 or a forgotten 1099 for the third time.
This checklist covers what to request from an individual client so you can start — and finish — without the back-and-forth.
Income documents
These report money the client received during the year.
| Document | What it reports | Who has it |
|---|---|---|
| W-2 | Wages from an employer | Every employed client — one per job |
| 1099-NEC / 1099-MISC | Freelance or contractor income | Self-employed or side-income clients |
| 1099-INT | Interest from bank accounts | Anyone with a savings account |
| 1099-DIV | Dividend income | Clients with brokerage accounts |
| 1099-B | Proceeds from stock or crypto sales | Investors — needed for capital gains |
| 1099-G | Unemployment or state refund | Clients who received either |
| SSA-1099 | Social Security benefits | Retired clients |
| K-1 | Partnership or S-corp share | Partners and S-corp shareholders |
A practical tip: ask clients to send every tax form that arrived in the mail or their inbox in January and February, even if they are not sure it matters. It is faster to discard an extra 1099-INT than to discover a missing one after you have started.
Deduction and credit documents
Whether the client itemizes or takes the standard deduction, these records determine credits and adjustments.
- 1098 — Mortgage Interest Statement (from the lender)
- 1098-T — Tuition Statement (from the college)
- Charitable contribution receipts (required for gifts over $250)
- Medical expense records (if itemizing)
- Child care provider info — name, address, and EIN — for Form 2441
- Estimated tax payments made during the year (dates and amounts)
- IRA and HSA contribution records
Before you can start: authorization and identity
For a new client, you also need the paperwork that lets you represent them and confirms who they are:
- Government-issued photo ID
- Social Security card or SSN confirmation
- Prior-year federal return (for carryovers and comparison)
- The right IRS authorization form — see Form 8821 vs Form 2848 for which one you need
The real problem is not the list — it is collecting it
Most preparers already know what to ask for. The friction is in the collection: email threads, files named "scan0043.pdf," documents that arrive one at a time over three weeks, and no clear view of what is still outstanding.
This is the gap tools like Intuit Link were built to close — with mixed results for many firms. We wrote an honest assessment in Intuit Link for accountants, and compared the options in our Intuit Link comparison.
The workflow that actually removes the chasing looks like this:
1. Send the client one secure link with this checklist already built in
2. The client uploads each document against the item it belongs to — no login, no app
3. You see, in one view, exactly what has arrived and what is still missing
4. Automated reminders handle the follow-up so you do not have to
That is the idea behind idutax: turn this checklist into a portal your client can actually use, and stop reconstructing status from your inbox. See how it works on our features page.
A reusable checklist beats a fresh email every year
The firms that stay calm in tax season build the 1040 checklist once and reuse it for every individual client, adjusting only the optional items. Whether you keep it in a document, a spreadsheet, or a client portal, the goal is the same: request everything up front, track it in one place, and never send a fourth follow-up email.