A 1099 form is a tax document used in the United States to report income received from sources other than regular employment, such as freelance work, independent contracting, interest, dividends, rental income, or other payments. Its primary purpose is to help the Internal Revenue Service (IRS) Internal Revenue Service track taxable income that may not be reported on a traditional employee W-2 form, ensuring that individuals and businesses accurately report their earnings and pay the appropriate taxes.