Filing Taxes for 3 previous years using TT Desktop Editions?

Just finished doing my Sister-In-Laws (SIL) taxes for 2022, both Fed and State using Desktop Edition Turbo Tax for PC, NOT on-line. 

IRS permits, I've read, allows individuals to file three (3) previous years only? So this, I would assume, would be for 2019, 2020, and 2021?

Here's my question(s): Since I have 2019, 2020, and 2021 Turbo Tax Desktop Edition still loaded on my home computer, (I'm a Computer Program Hoarder 😁), I know I can fill them out (she's retired and not much income) and is possibly/probably due a refund from her small retirement accounts, can I e-file these returns, or do I have to print them out and use the USPS to send them?

I would much prefer to e-file, but can have her sign and date when I complete the Returns.

Thanks in advance for your help/advice! Much appreciated!

Jon