How to access prior online returns
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/01/270...
You have to log in to the same account. You need to start entering some basic Personal Info in 2021 for the side menu to open up. Just continue a little ways into 2021.
If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online.
You can also request a transcript from the IRS
Get Transcript | Internal Revenue Service
