If you are preparing a 2020 return you can still use the recovery rebate credit section in Federal Review to get the 1st and/or 2nd stimulus amount. You cannot e-file 2020. It can only be filed by mail. You have three years from the origjnal filing deadline in 2021 to file a 2020 tax return and still receive your refund.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.