I have already filed my taxes for 2019-2020. And they have already have been accepted. How can I enter it?

I assume you want to enter something else on your tax return. Since your return was accepted by the IRS, you must prepare, print, sign and mail an amended tax return form 1040X to correct the problem. The form will not be available in TurboTax until later in February.

DO NOT change your original tax return until you start the amended return. If you have already changed it from the way it was originally filed and accepted, you must change it back before you start the amended return. Wait until you receive the refund from your original return before beginning your amended return to make sure you enter the correct amount. Here is an FAQ to help you:
https://ttlc.intuit.com/questions/1894381-how-to-amend-change-or-correct-a-return-you-already-filed