Personal pronouns :

Used instead of a name of a person, place, object, or idea when it is clear what or who you are talking about.

Pronuns save us a lot of repetition.

Examples :

Bob, Tubai and I decided that we would watch the flamingos from our terrace

Bob stayed back as the watchman did not see him

When the watchman saw Tubai and me on the terrace, he asked us to come down

The Flamingos are the beautiful birds; It’s a pleasure to watch them

Some personal pronouns serve as subjects and some of objects in sentences

Subjects Pronouns

Pronouns that replace subjects nouns

Subjects pronouns are : I, you, he, she, it, we they

For example :  She went home

Objects Pronouns

As the object of a verb  or preposition  in the predicate

Objects Pronouns are : me, you, him, her, it, us, them

For example : He went with her