How can I change my filing status to head of household on this form? Turbo Tax chose single?

Did you claim a qualified dependent?   (A GF or BF cannot be a qualified dependent for HOH filing status).

 

Am I Head of Household?

 

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-filing-status/qualify-head-household-2021/L0NxUtVc2_US_en_US?uid=m5x19jkx

• What is a "qualifying person" for Head of Household?

 

If you qualify as Head of Household, when you enter your marital status (single or married filing separately) into MyInfo, and then enter your qualifying dependent, TurboTax will offer HOH as your filing status.

 

You will have to go back to the "About me" section of the program and go through the interview again.  You will need to answer the questions in a way that indicate you are eligible for head of household filing status.