Where do I enter additional tax payments made in 2025 towards 2024 tax year.

[AstuteO]

Look at the "Payments" section of the form 1040, where you have several places to list different ways you paid 2024 taxes.
If you paid taxes along with your extension (form 4868) that you probably filed sometime before April 15, then that amount goes onto line 31 -- but they make it confusing, because you need to go to "schedule 3, line 15".  On schedule 3, you will list the amount paid with your extension, and then that will also be what you show on line 31. 

[VolvoGirl]

What kind of payments did you make?  How did you make them?

To enter Federal or State Estimated Taxes Paid, including a state estimated payment made in January for the prior year, go to

Federal on left or at top (Personal for Home & Business)

Deductions and Credits

Then scroll way down to Estimates and Other Taxes Paid

Estimates - click the Start or Update button
If you made more than 4 payments - at the bottom is + Add another payment

For a payment made with an Extension to file go to….

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

Federal Estimated payments should be on 1040 line 26.
Federal Extension payment should be on schedule 3 line 10 which goes to 1040 line 31.

[db]

To clarify, I meant additional payments made after filing for an extension and found the right place: Under Estimated Taxes section with four quarters, there is a button "Other Tax Payment" and that lets you enter a date with an amount.