Are you asking about an estimated tax payment that you made in January 2024 or in January 2025? I think you meant that you made the payment in January 2024, but VolvoGirl thinks you made it in January 2025.
An estimated tax payment in January normally is the final payment for the preceding year. A payment in January 2024 would be for 2023 tax, and a payment in January 2025 would be for 2024 tax.
When you make an estimated tax payment you have to designate what year it's for. If you mailed a check with Form 1040-ES, the form has the year on it. If you made the payment online you selected the year that it was for.
If you have an IRS online account, the payment history in your online account should show which tax year each payment was for. Your accountant, with your permission, can also look up your payment history.
If you filed a tax return showing incorrect payments you should file an amended return. If it was the accountant's error, he should prepare the amended return at no charge. I don't know what you mean by "do it informally." There is no informal way to correct a tax return. The only way to correct it is to file an amended return. However, the IRS might catch the error and correct it without you having to do anything, since they have the records of your actual payments. So you might want to just wait until the IRS has processed your tax return and see what happens. Ask your accountant what he thinks you should do.
