Every person applying for work in the United States must fill out a federal Employment Eligibility Verification form, known as the I-9. Both citizens and non-citizens must complete this form. The form is kept by the employer and must be available for the government to check to make sure the company is only employing people authorized to work in the United States. According to federal law, the I-9 form must be kept at least three years after hiring an employee or one year after the employee is dismissed, whichever is later.