CAN I USE TURBO TAX TO FILE A MD STATE RETURN FOR 2020?

No---for a number of reasons.   TurboTax no longer provides software or supports the software for 2020.   Even you had the software for 2020 and used it for your federal return, you can no longer get the state download.  

You may be able to get the paper forms from the state's website to prepare and mail in, or you can seek local paid tax help for a 2020 return.   You should be aware that it is too late to receive a refund for a 2020 return, but if you owe tax to the state, it will be with late filing penalties and interest.

You can’t do it online. You would have to find the desktop version and print and mail your return. 

TurboTax does not support tax year 2020.

You can call the Maryland Comptroller for assistance in providing a 2020 MD state tax forms - 1-800-MDTAXES