Nov 4, 2023 — Form W-7 (with Individual Taxpayer Identification Number). Request for Taxpayer. Identification Number and Certification. ▷ Go to for instructions and the latest information. Give Form to the tax office at the address above is open Monday through Friday, 8:00 a.m. to 4:30 p.m., and Saturday 9:00 a.m. to 3:30 p.m. Call, or email: fwofficefortworthtx.gov. Go to the address to the tax office. Taxpayer's Responsibility for Filing Returns With Information Returns: When you file your return, you are responsible for maintaining adequate documentation of your tax liability. Failure to complete this form, and any required information returns, may result in penalties and the imposition of audit action. The Form W-9 information returns are filed by the filer who actually filed the return and are considered part of the taxpayer's filing. The original Form W-9 or other proof of an individual's tax return is required and must be kept with records for 10 years. See the Forms you must file to file a tax return.