Possessive nouns are used to indicate ownership.
1. Possessive nouns usually are formed by adding an apostrophe (') and s. Ex : Ram's book / Rohan's Car.
2. When a noun is plural and ends in s, just add an apostrophe ('). Ex : The kids' toys.
3. If two people own one thing, add the apostrophe and s to the second person only.Ex : Ram and Sohan's new house.
4. If two people own separate things, add the apostrophe and s for each person. Ex : Sita's and Geeta's books.