IRS Form W-9, Request for Taxpayer Identification Number and Certification, is an application which a taxpayer (a recipient) is required to fill out by an entity or an individual (a requester). This form is required because the requester must receive the recipient's correct Taxpayer Identification Number (TIN) in order to submit an information return to the Internal Revenue Service (IRS) on the amount paid to the recipient. The newest version of this form was released by the IRS in October 2018.
For example, when a company makes certain payments, they have to report them to the IRS. One of the most commonly used applications for it is Form 1099-MISC, which reports miscellaneous payments by entities. These payments can include things such as prizes, awards, gross proceeds, payments for services, medical payments, rents, nonemployee compensations, etc. In order to fill out Form 1099-MISC, an entrepreneur must know certain information about the receiver of the payment: name, address, and TIN. Since incorrect information submitted to the IRS is considered perjury, Form W-9 is needed here as an official request to the taxpayer to provide their correct TIN and certify that the number shown on the form is valid.
A taxpayer can be requested to fill out a W-9 tax form by a third party who is required to file an information return with the IRS. The form will be mailed or emailed to the taxpayer with a demand to send it back. A fillable version of the IRS W-9 Form is available for download below.