A noun can generally be used as a possessive noun just by adding an apostrophe and an ‘s’ at the end of the noun. Similarly, pronouns can be used to show possession too. It is not by adding an apostrophe or an ‘s’. There are pronouns that exclusively function in order to show that a particular person, animal or object belongs to a particular someone.
1. For the personal pronoun, ‘I’, the possessive pronoun would be ‘mine’.
For example, to indicate that ‘I own that blue car.’, it can be written as ‘That blue car is mine.’
2. For the personal pronoun ‘we’, the possessive pronoun would be ‘ours’.
For example, to indicate that ‘the project that won the first prize belongs to us’, it can be written as ‘The project that won the first prize was ours.’
3. Similarly, for the personal pronoun, ‘he’, the possessive pronoun would be ‘his’.
For example: It is Kim’s pet cat.
It is his pet cat.