her is a possessive adjective used to refer to something or someone that belongs to a female person. For example, 'her hat' or 'her student.'
her can also be a possessive adjective, which is used to indicate possession or ownership of a person. For example, 'This is her bag,' or 'That is her car.' Her cannot be used as a pronoun to refer to a collective group of people; instead one would use 'theirs' (e.g., 'They shared their final project'). Her is always written as a single word; it should never be spelled 'hir,' for example.
1) Ellen passed her final exam with flying colors.
2) Her shoes were a perfect match for her dress.
3) She often caught her brother hiding in her room.
when using her as a possessive adjective, be sure to remember that it must refer to a female person or thing - it cannot be used to refer to a male person or thing. Additionally, her will always be written as one word - other spellings such as 'hir' are incorrect.