Internal Revenue Service
- Home page
- Refund Tracker
- IRS Forms
- Withholding Calculator
- Employer’s Tax Guide
- Online Payment Agreement Application
- Form SS-4 Application for Employer Identification Number
- Form W-4 Employee’s Withholding Allowance Certificate
- Form W-9 Request for Taxpayer Identification Number and Certification
- IRS You Tube Video Channel
- IRS Telephone Numbers (Third-Party Site)