A possessive pronoun refers to a thing or person and its owner: my, your, mine, yours, etc. Sometimes possessive pronouns are called possessive adjectives.
1)The possessive pronoun (my, your, his, her, its, our, their) always stands before a noun and modifies it.
E.g. My aunt is a professor. Is this your house?
2)The possessive pronoun (mine, yours, his, hers, its, ours, theirs) replaces a possessive pronoun and a noun when the noun is understood.
E.g. The book on the desk is mine, and yours is in your schoolbag.