The purpose of Form I-9 is to document that each new employee (both citizen and non-citizen) hired after November 6, 1986 is authorized to work in the United States. All employees (citizens and non-citizens alike) hired after November 6, 1986 must complete a Form I-9. The employee as well as the employer are required to sign Form I-9.

Form I-9 must be completed no later than at the time of hire (the actual beginning of employment). Providing applicant's social security number is voluntary and it is up to the employer to ensure that Section 1 of Form I-9 is timely and properly completed.

For purposes of Form I-9, noncitizen nationals of the United States as persons born in American Samoa, certain former citizens of the former Trust Territory of the Pacific Islands, and certain children of noncitizen nationals born abroad.

Employers must fill out Section 2 of Form I-9 by examining evidence of identity and employment authorization within three business days of the commencement of employment. The acceptable forms of identification and employment authorization are provided in List A, B, and C on the reverse side of Form I-9. Employers are also required to reverify employment authorization for employment on or before the date shown. (Some employees may leave the Form I-9 expiration date space blank if they are aliens whose work authorization does not expire such as, asylees, refugees, or certain citizens of the Federated States of Micronesia or the Republic of the Marshall Islands.

A Preparer/Translator Certification must be completed and signed if Form I-9 is prepared by a person other than the employee (this is allowed only when the employee is unable to complete Form I-9) on his own. However, the employee must sign Section 1 of Form I-9 on his own.