Filing head of household is usually for an individual who has dependents and is single. Filing single is if you have no dependents and only file for your self
Head of household will give you more benefits than single. You will get a larger exemption to start with and any additional exemptions will also be higher. Also as head of household you will pay less taxes than a single.
To file as head of household, you must meet certain criteria as the provider for dependents that meet a particular set of circumstances. Single living alone will not qualify.