Your kids.  Your fiancée could also place you in that filing status, but only if you paid for over half of their care and they fulfill the requirements of a dependent.  To see if they qualify as a dependent and if you can claim them on your taxes, please use the IRS interactive tool Who Can I Claim As A Dependent.  Head of Household is a filing status such as filing single or married filing jointly.  In order to qualify for head of household a few of the requirements is that you are unmarried and have at least one dependent.  To learn more about this filing status, please see the Turbo Tax article below.

https://ttlc.intuit.com/replies/3288637