It is not an estimated tax payment. Example: I want to pay some amount on February 10, 2025, using the IRS account payment function for a partial payment. Then, when I actually file I want to pay a second amount using Turbotax. So I have an early payment on February 10, then, on April 10, 2025, send the remainder. Before turbotax, there was a line on the paper forms for other additional payments.
