If you have a file ending in .tax2021 you need the 2021 Desktop program installed to open it. You probably want the pdf file.
How to Access prior year online returns
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/00/270...
If you can't get the side menus to open up to access the prior year..... You need to start entering some basic Personal Info in 2024 for the side menu to open up. Just continue a little ways into 2024. I had to go though about 12 screens.
If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online. So you need to make and keep your own backups.
Or request a transcript from the IRS
https://www.irs.gov/individuals/get-transcript
Or get a copy of your return using form 4506
https://www.irs.gov/pub/irs-pdf/f4506.pdf
