I-9 refers to a form issued by the Department of Homeland Security, U.S. Citizenship and Immigration Services (USCIS).
Employers are required to complete a Form I-9 "Employment and Eligibility Verification" for all newly hired employees to verify their identity and authorization to work in the United States. This applies to both U.S. citizens and non-U.S. citizens. The requirement is set forth by section 274A(a)(1)(B) of the Immigration and Nationality Act (8 U.S.C. 1324a(a)(1)(B)).
The employer is responsible for ensuring that each employee completes Form I-9 at the time of hire. Employees must provide documents that establish both identity and employment eligibility from a list of acceptable documents as determined by USCIS.
There is no fee associated with Form I-9 and it is not filed with USCIS or any government agency. However, the form must be available for inspection by authorized U.S. Government officials (e.g., Department of Homeland Security, Department of Labor, Office of Special Counsel). It is the employer's responsibility to complete and retain the form.
Employers must retain completed Forms I-9 for 3 years after the date of hire or 1 year after the date employment ends, whichever is later.
Source: USCIS
