During everyday bath one has to do achamana, pranayama, chant that day’s tithi, and star, then chant ‘karmanyatA sidhhyarthaM prAtaH snAnaM ahaM kariSyE’ and take a bath.
Generally, taking a bath includes a head bath.
Brahamacharis need not take a head bath every day.
Taking a bath implies a head bath too but if it is not possible there are subdivisions to it.
For example, when we do not feel well, taking a bath until the neck is permissible.