Form W-2 is a tax document that employers in the United States must provide to their employees. It reports the annual wages earned and the taxes withheld from those earnings. Employees use this form to complete their income tax returns, ensuring they accurately report their income and any taxes owed or refunded. Each W-2 form includes important information such as the employee's Social Security number, the employer's identification number, and details about federal, state, and local taxes withheld. Employers must send W-2 forms to their employees by January 31 each year, allowing ample time for tax filing.