I haven't used Turbo Tax for several years, & my husband died in 2021. I'm wanting to use turbo tax again, but the system still thinks I'm married. How do I resolve this?

It is best to start a new account with a new user ID.   It is too difficult to delete the embedded information from a spouse if you use the same account that was used for past joint returns.

The TT file will include a Personal Wks form (go to View Forms).  There is a line to put in date of death if the person is deceased.  Not sure what documents would carry over from 2021 so starting a new file might be the cleanest.