Cannot upload last year's tax data. Last year had a CD desktop version. Online this year. Requires pdf upload. Get error "Taxpayer's complete Name missing" from pdf.

[DoninGA]

Use the tax data file from the 2020 tax return on your computer to transfer to the 2021 online return.

The tax data file will have a file extension of .tax2020 and is by default in the TurboTax folder within the Documents directory.

[VolvoGirl]

You can transfer from the prior year on your computer into the Online version. You will need to have the .tax2020 file on your computer. If you used the Desktop program last year 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-turbo...

If you already started an online return you will have to clear it and start over to transfer. How to clear and start over
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-onli...

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. You can only do 1 return. Your return is only saved online so be sure to save both the .tax2021 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.