See this TurboTax support FAQ for how to transfer the 2021 return from a computer to the 2022 online editions - https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/transfer-last-year-return-turbotax-online/L279eUvY2_US_en_US?uid=lnhpnqbx
You shouldn't use the pdf file. You need the data file ending in .tax2021. Do you have it? It should be in your Documents in a Turbo Tax folder. Or search your computer for all files ending in .tax or .tax2021. Are you on Windows or Mac?
If you used the Desktop program last year here’s How to transfer into the Online version. You need to have the prior year .tax2021 file on your computer. Expand the link if you used the CD/download last year........
https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/transfer-last-year-return-turbotax-online/L279eUvY2_US_en_US?uid=l8w7nlbv
Or here’s How to switch and transfer from the Desktop program into the Online version........
https://ttlc.intuit.com/community/tax-topics/help/how-do-i-switch-from-turbotax-cd-download-to-turbotax-online/00/859756
If you used the Desktop program before you may notice several differences and not like the online version. It has less features and no Forms Mode. The Online versions don't have all the same forms so you might have to upgrade to a higher Online version. You can only do 1 return. Your return is only saved online so be sure to save both the .tax2022 data file and the pdf file to your computer when you are done. In case you need to amend in the future or if you need a copy to get a loan or something. You might not be able to access your online return when you need a copy.