Financial Aid offices can be pretty dim. What do they actually want? If they want to see a tax return, you can prepare one, file by mail, and give them a copy of the signed return. (Because of the backlog, it won't be in the online transcript system for a long time, probably months.)
Maybe you can show them your W-2 and that your income was so low you were not required to file.
If you filed before, just not last year, you can get an account transcript, that might satisfy them that you didn't file and don't owe tax. (If you have never filed a tax return, you won't have an account to look up.)
It's hard to know how to satisfy them, ask them what do they really want to know?
