Possessive pronouns

Possessive pronouns are used to talk about who owns something.
We use possessive pronouns to avoid repeating the noun.
This is my car, not your car. (this sentence is correct grammatically but not natural)
This car is mine, not yours. (natural)

Note :

A possessive pronoun is not used before a noun.

Subject	Possessive Pronoun
I	mine
you	yours
he	his
she	hers
it	its
we	ours
you	yours
they	theirs

Examples :

This book is mine.
I like that car. Is it yours?
It's not your pen. It's hers.
We have a new house. It's ours.
Our work is finished; theirs isn't.
Your computer is better than mine.