Do you have any dependents or children? You can't check the HOH box until you have entered dependent info and ssn. You select Head of Household under My Info. Edit your name.
See IRS Pub 501 page 10 for qualifying person.
https://www.irs.gov/pub/irs-pdf/p501.pdf
Who is a qualifying person for Head of Household
https://ttlc.intuit.com/community/family/help/what-is-a-qualifying-person-for-head-of-household/00/2...
