2020 information can significantly affect your 2021 return.
When completing the return it will ask for the AGI (adjusted gross income) from your 2020 tax return. This isn't the W2 amount. You'll need a copy of your 2020 return to get the AGI from the form 1040 line 11. If you can't locate it you will need to mail in the return.
In order to transfer 2020 in to 2021 you have to use exactly the same account and user ID and do that transfer at the very beginning before you enter any new 2021 data at all.
Many people have multiple TT accounts and forget how to access them. Log out of the account you are in now.
Account recovery
https://myturbotax.intuit.com/account-recovery/
How to transfer last year’s return? https://ttlc.intuit.com/questions/1900883
You will need the AGI ( adjusted gross income) from line 11 of 1040 form from 2020 return to efile your 2021 return.
Do not enter 2020 numbers on your 2021 tax return.
If the form is not relevant this year, delete it.
When you go to file the return, it will ask for your AGI (adjusted gross income) from your 2020 return. You can find that on the main tax form 1040 on line 11. It is not on your W2 or anywhere else. It's used for security purposes. If you don't have access to your 2020 return you will need to mail the return without that information.