If your extension payment did not automatically show up on your 1040 or state return you need to enter it. So make sure it's not already there before you enter it!
To enter the amount you paid with an extension (including state extension) go to
Federal Taxes (or Personal for desktop H&B version)
Deductions and Credits
Then scroll way down to Estimates and Other Taxes Paid
Other Income Taxes - Click the Start or Update button
Next page second section Payments with Extension
Either Visit All or Click Start or Update by the extension you paid
When you requested your extension you were supposed to pay your estimated tax due. Did you enter the payment you made into your tax return?
Go to Federal>Deductions and Credits>Estimates and Other Taxes Paid>Other Income Taxes
Beyond that---just prepare and file your return. The IRS already knows you have an extension. You do not enter anything about that on the Form 1040.
If your extension payment did not automatically show up on your 1040 or state return you need to enter it. So make sure it's not already there before you enter it!
To enter the amount you paid with an extension (including state extension) go to
Federal Taxes (or Personal for desktop H&B version)
Deductions and Credits
Then scroll way down to Estimates and Other Taxes Paid
Other Income Taxes - Click the Start or Update button
Next page second section Payments with Extension
Either Visit All or Click Start or Update by the extension you paid