Assuming she has an online return and you installed the Desktop program.
First download her tax file from the Online version as a .tax2021 file
https://ttlc.intuit.com/community/saving/help/how-do-i-save-my-turbotax-online-return-as-a-tax-data-...
Then just open it in your program. Go up to File-Open. Is she in the same state as you? See How to Switch to Desktop,
https://ttlc.intuit.com/community/choosing-a-product/help/how-do-i-switch-from-turbotax-online-to-th...
Or you do want to download her 2020 online return to transfer into 2021? You can do that too.
