Form W-4 https://www.irs.gov/forms-pubs/about-form-w-4 Form W-9 https://www.irs.gov/forms-pubs/about-form-w-9 Form I-9 https://www.uscis.gov/sites/default/files/document/forms/i-9-paper-version.pdf Where’s My Refund https://www.irs.gov/refunds
