After you file

@xmasbaby0   The Forms Availability list says the 1040X is available.  But they haven't updated this amend FAQ for 2021 yet.  Is there a newer amend article?  Can you check with them?

https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-...