The extension payment should be a credit on your tax return.  For 2020 Federal Extension payments should be on schedule 3 line 9.  And go to 1040 line 31.

If your extension payment did not automatically show up on 1040 Schedule 3 line 10 which goes to 1040 line 18d you need to enter it.  So make sure it's not already there before you enter it!

You can type estimates paid in the search box at the top of your return and click Find and it will give you a link to Jump To the screen where you enter Extension Payments.

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

@xmasbaby0   OMG, This was perfect!!  Thank you for the detailed pathway.  I entered the amount I paid at the time of my extension and my refund status changed to include that amount.  Thank you 🙏

@VolvoGirl   Thank you for the detailed payment to resolve my issue.  It is greatly appreciated!!