The W-2 form, officially the Wage and Tax Statement, is a crucial document from employers detailing annual income and taxes withheld, including federal, Social Security, and Medicare taxes. It is essential for accurately filing federal and state tax returns and may also list benefits like health insurance and retirement plans. Employers must send W-2s by January 31 annually to both employees and the IRS. Individuals earning $600 or more from an employer receive this form, while independent contractors typically receive a Form 1099 instead.