Change to head of household. It isn't giving me an option on my tax forms to change my setting to Head Of Household. i have been living on my own for the last 3 years and

To use the Head of Household status there are some requirements you must meet:

1. Were unmarried as of December 31, 2023 and
2. Paid more than half the cost to run your (or a qualifying parent's) home this year (rent, mortgage, utilities, etc.) and
3. Supported a qualifying person.

If you were still legally married as of December 31, 2023, and a child lives with you, you can qualify for Head of Household under a slightly different set of rules. 

After you answer all the questions about yourself and your dependents at the beginning of your return, we'll let you know if your situation qualifies for Head of Household.

You can also revisit these questions by selecting My Info (online) or Personal Info (software) and then selecting Edit next to your name or your dependent's.

If you do not have a qualifying person you will not be able to use the Head of Household status.  

"living on my own"   does not mean you can file as Head of Household.  In order to file as HOH, you must have a qualified dependent.   

Am I Head of Household?

https://ttlc.intuit.com/questions/1894553-do-i-qualify-for-head-of-household

https://ttlc.intuit.com/questions/2900097-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.