I used to be married but the divorce was finalized in2019 why is turbo tax including my ex-husband in the questions? How do I change it to file single?

You need to start a new account for yourself with a different user ID and use that account for your Single filing status.   It is too hard to remove the "spouse stuff" from an account that was previously used for joint returns

https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-online/00/25596

How did you file for 2019?  You should have set up your own account last year and filed as Single.  If you did start your own account you need to log into that account. Are you in the wrong account?

First LOG OUT of whatever TurboTax account you're logged into right now. Then use this TurboTax account recovery website to get a list of user ID's for an email address. Run the tool against any email addresses you may have used
https://myturbotax.intuit.com/account-recovery/