Your filing status is determined by your status as of 12/31 of your tax year. There are options since it seems from your question you were still married as of 12/31/21.
There are different situations that are necessary for each option as well as some options that deny you some credits. Since I don't know your whole situation, please see What is my tax filing status (single, married, etc.)? for the best info to help you out.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"