W9 Forms 2021 Printable When they are working as a freelancer or independent contractor, people most frequently use IRS Form W-9. Whenever you ever find yourself filling out a Form W-9, it indicates that a company or individual who is paying you money requires your Social Security number so it can alert the IRS of the quantity. The W-9 is used in a large range of payment circumstances, however the majority of frequently, taxpayers fill them out when they are working as a freelancer or independent professional rather than a worker.W9 Forms 2021 Printable