A W-2 form is a tax document that employers in the United States provide to their employees. It reports the employee's annual wages and the amount of taxes withheld from their paychecks throughout the year. Employees use this information to file their income tax returns. The W-2 form includes details such as the employee's Social Security number, the employer's identification number, and the total earnings for the year. It is typically issued by the end of January each year, allowing employees to prepare their taxes accurately and on time.