When you fill out the Personal Info section of TurboTax, TurboTax will determine whether or not your situation qualifies for Head of Household. You can double-check your entries in this section to make sure that all of the information has been entered correctly. To do this, go to the Personal Info tab, then select Edit next to your dependent's name.
To qualify as Head of Household, you must meet the following requirements:
Pay for more than half of the household expenses
Be considered unmarried for the tax year, and
You must have a qualifying child or dependent.
You can find out more information about the requirements for filing as Head of Household here.