In terms of wajib, it is wajib to cover the private parts Infront of mahram men (excluding the husband). Women can reveal their hair and makeup to their mahram men such as father, brother, grandfather.

With Na mahram men, everything has to be covered apart from the face and hands (wrists down). This is the physical hijab. There is also the social hijab that is observed in interactions with Na mahram men such as in work places and schools, university