Which form is crucial for verifying eligibility to work in the U.S.?

The I-9 form is essential for verifying an individual's eligibility to work in the United States. This form must be completed by both the employer and the employee at the time of hire. It requires the employee to provide documentation that establishes both their identity and their authorization to work in the U.S. The form facilitates compliance with immigration laws, ensuring that employers do not hire individuals who are not authorized to work in the country.

The other forms mentioned serve different purposes. For example, the W-4 form is used by employees to indicate their tax withholding preferences for income tax purposes. The 1040 form is the individual income tax return form that taxpayers use to report their income to the IRS and calculate their tax liability. The SS-5 form is an application for a Social Security card, which is not directly related to employment eligibility verification. Thus, the I-9 form stands out as the specific document required for confirming work eligibility.