- W-9 Request for Taxpayer Identification Number and Certification
To obtain correct taxpayer ID number. REQUIRED by FEDERAL LAW for payments to non-employees (independent contractors). - Circular E Publication 15
Payroll Tax Withholding Tables - W-4 Request for Taxpayer Identification Number and Certification
Must be completed so the employer can withhold the correct Federal income tax. REQUIRED by FEDERAL LAW. - IRS Website