See this TurboTax support FAQ for transferring a 2020 PDF to TurboTax 2021 for Windows - https://ttlc.intuit.com/community/using-turbotax/help/can-i-transfer-last-year-s-pdf-into-the-turbot...
It would be better to transfer from the 2020 tax data file from the online return to the 2021 return instead of the PDF.
To access your prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/
Scroll down to the section Your tax returns & documents. Click on the Year and Click on Download .tax file
See this TurboTax support FAQ for transferring a 2020 tax data file to the 2021 return - https://ttlc.intuit.com/community/entering-importing/help/transfer-last-year-s-return-to-turbotax-fo...
