1) Common nouns
Common nouns name any person, animal, place or thing. They begin with small letters unless they come at the beginning of a sentence.
Examples:
They live in a city.
It is his dog.
She eats a banana.
2) Proper nouns
Proper nouns are the names of specific people, animals, places or things. They should begin with capital letters.
Examples:
They visited New York in 1991.
His dog’s name is Max.
She will start work on Monday.