Foreign Vendor Questionnaire. Give Form W8 BEN to the withholding agent or payer if you are a foreign person and you are the beneficial owner of an amount subject to withholding.Complete Part XI. Nonreporting IGA FFI. Understand their roles of W8 vs. W9 forms in U.S. taxation, key differences, and get insights on how to fill them out. The Form W9 is a short onepage form that asks for your name, address, and IRS tax identification number (SSN or ITIN in the case of an individual). Foreign vendors do not complete the Substitute Form W-9; foreign persons or entities must submit one of five available forms. 9 form is an Internal Revenue Service (IRS) tax form that is used to confirm a person's name, address, and taxpayer identification number (TIN) Form W9 is only for US individuals. If you are a non-US individual then you need to be completing a W8.