If you are mailing your Federal Extension, refer to the 4868 instructions for the most up to date mailing addresses.
What do I need to include with my extension?
Mailing payment with extension
If you intend to mail in your payment with your extension, you will need to print and mail your Form 4868 with the payment.
Be sure to make your check or money order payable to the "United States Treasury." Write your social security number, daytime phone number, and "Form 4868" on your check or money order. Do not staple or attach your payment to Form 4868.
What if I file the extension electronically and wish to mail the payment?
Print and mail your Form 4868 with the payment - even if you electronically filed your extension. The completed paper Form 4868 will be used as a payment voucher. With the payment and voucher, note that you originally e-filed your extension request.
How do I print my extension?
For printing instructions, Click here.