The TurboTax program will give you Head of Household status only if you are eligible.
See this TurboTax support FAQ for HOH - https://ttlc.intuit.com/community/family/help/do-i-qualify-for-head-of-household/01/25539
Are you eligible?
Go to the MY INFO tab and edit the filing status. If you have a qualifying child the program should let you change to HOH. If you do not then you must enter a qualifying person first.