A W-9 form is a document used in the United States by the Internal Revenue Service (IRS) to collect taxpayer information. It is typically filled out by individuals or businesses that are not employees but are providing services to a company. The form includes details such as the name, address, and taxpayer identification number (TIN) of the individual or entity. When a business hires a contractor or freelancer, they may request a W-9 to ensure they have the correct information for tax reporting purposes. The information provided on the W-9 helps the business issue a 1099 form at the end of the year, which reports the income paid to the contractor.