The noun is a name of a person, place, animal, or thing.
A pronoun is a word that is used instead of a Noun.
For example.
Ram is a boy. He has a dog
In this sentence, Ram is a noun, and "HE" is a pronoun that is used instead of Ram ( Noun)
The table is beautiful but it is very expensive.
In this sentence, Table is a noun and 'IT' is a pronoun which is used instead of the table ( Noun )