How to Fill Out Form I-9 — Employee & Employer Guide

Every U.S. employer must complete Form I-9 for every person they hire — citizens and noncitizens alike. The form is a shared responsibility with hard deadlines: the employee completes Section 1 by the first day of work, the employer completes Section 2 within three business days. This guide walks both halves. Need the form itself? Fill it with our free I-9 filler — it runs locally in your browser.

Section 1 — the employee's half

Fill this on or before your first day — not after. The fields:

Legal name — as it appears on your documents. “Other last names used” covers maiden or former names; write “N/A” if none, don't leave it blank.
Address and date of birth — a current physical address; P.O. boxes aren't accepted.
SSN — voluntary, unless your employer uses E-Verify, in which case it's required. Ask HR if unsure.
Status checkbox — exactly one: U.S. citizen, noncitizen national, lawful permanent resident (with your USCIS/A-number), or alien authorized to work (with expiration date and USCIS/I-94/foreign passport number).
Signature and date — an unsigned attestation is the single most frequent finding in I-9 audits.

Choosing your documents — List A or List B + C

You prove identity and work authorization with documents from the Lists of Acceptable Documents, and the choice is yours, not your employer's:

One document from List A — proves both identity and authorization: a U.S. passport or passport card, a permanent resident card, an employment authorization document (EAD), or a foreign passport with an I-94.
Or one from List B plus one from List C — identity (e.g. driver's license, state ID) plus authorization (e.g. an unrestricted Social Security card, a birth certificate).

Documents must be unexpired originals — no photocopies, no expired cards (a formal receipt for a replacement document is the narrow exception). If an employer demands a specific document or asks for more than required, that's document abuse — unlawful even when well-meant.

Section 2 — the employer's half

Within three business days of the employee's start date, the employer (or an authorized representative) must:

Physically examine the original documents — since 2023, employers enrolled in E-Verify in good standing may use the alternative remote examination procedure instead; everyone else verifies in person.
Record each document's title, issuing authority, number and expiration date in Section 2.
Enter the employee's first day of employment, then sign and date the attestation.

Do not backdate anything. If you discover an error later, correct it with a single line through the entry, initials and the current date — and attach a note for material corrections.

After the form: retention and reverification

The I-9 is never filed with USCIS. The employer keeps it for three years after the hire date or one year after employment ends — whichever is later — and produces it on inspection. If the employee's work authorization has an expiration date, reverify it in Supplement B (formerly Section 3) no later than that date; U.S. citizens and permanent residents never need reverification. Set the reminder the day the form is completed, not when you happen to remember.

The mistakes audits actually find

Missing signatures or dates in either attestation.
Section 1 completed after day one, or Section 2 after the three-business-day window.
Accepting expired documents.
Telling the employee which documents to bring (their choice, always).
Completing the I-9 before the job offer is accepted — pre-screening risks discrimination claims.
Forgetting to reverify expiring authorization in Supplement B.

Fill out Form I-9 now — free, no upload

This guide is general information, not legal advice. Requirements change — check the current edition date and official instructions at uscis.gov/i-9. Employers with specific questions should consult counsel.