I know the IRS allows efiling from previous years. So, to confirm your reply, efiling previous years returns is not a feature of Turbo Tax. Ergo, to file 2019, 2020, and 2021 taxes completed in Turbo Tax, they have to be mailed in.
What if I don't have any corroborating documentation? My new son in law hasn't done his taxes in the past. I had to go to his transcripts on the IRS website to get the information I used to fill out his previous years.
Thanks for your help
