How to fill out IRS Form W9. How to fill out IRS Form W9. Modify the PDF form template to get a document required in your city. Then just send it to the IRS! How to fill out IRS Form W-1 (Form W-2 or Form W-3?) — IRS Form W-4, Request for Taxpayer Identification or Certification. If the information on Form W-4 (Form W-4/Form W-3) is: Name of the Federal Government Agency Type of tax return requested Purpose of request Explanation of the information for which taxpayers are asked to supply information In general, form W-4/4a is only required if you are a United States citizen. However, you should obtain this form only if you have not claimed a refund for the taxes and items described in this instruction (see section 7.4). If a nonresident alien, a nonresident alien social security number holder or a nonresident alien employee and/or owner of an LLC, you are not required to fill out Form W-4 for Form W-4.2 as you filed a claim for credit based on the foreign status of the taxpayer. If you filed the return for the same return period, and you are a nonresident, you may be required to answer the question as to the tax imposed by this form if you did not claim a refund. Form W-4, Request for Taxpayer Identification or Certification. If Form W-4, Request for Taxpayer Identification or Certification is mailed to you, it: Should not be mailed. If not mailed, fill out a paper form and return the paper return and Form W-4 to the Treasury Inspector General for Tax Administration (TI GTA) on Form 8629, Form 1142, Form 6038, Form 7536 or Form 7410. If the information on form W-4 is: Name of the Federal Government Agency Type of tax return requested Purpose of request Explanation of the information for which taxpayers are asked to supply information In general, Form W-4/4a is not required if you are a United States citizen. However, you should obtain this form only if you have not claimed a refund for the taxes and items described in this instruction (see section 7.4). A Non Citizen may be required to answer the question as to the tax imposed by this form.