Government Sites Internal Revenue Service   An online resource to find the latest in tax law   IRS Forms (Downloadable) Employee Withholding Form W-4   W-4 form can be used to change withholding on a paycheck. SS-4 Request for ID Number for New Business   If you need an ID number for a new business, you can request it online. Subcontractor Request for ID Number Form W-9   If a non-employee needs to receive a form 1099, they need to give this form to the payor. Form 4868 Extension of Time to File   This form gets an individual 6 extra months to file their return (this is not an extension of time to PAY). IRS Estimated Tax Forms 1040ES   Use form 1040ES to pay your estimated taxes.   Online Tax Payments Pay Federal Taxes   PAY1040.com allows you to pay your Federal income taxes electronically.