Personal Pronouns:

Use personal pronouns to replace nouns. They are: I, you, he, she, it, we, you(plural), they, and me for subjects pronouns, you, him, her, it, us, you, them for the object pronouns.

Structure:

Personal pronouns in the subject affect the conjugation of the verb whereas this is not the case for object pronouns.

Examples:

I like to go on vacations. It belongs to me.
You like to go on vacations. It belongs to you.
He likes to go on vacations. It belongs to him.
She likes to go on vacations. It belongs to her.
It likes to go on vacations. It belongs to it.
We like to go on vacations. It belongs to us.
You like to go on vacations. It belongs to you.
They like to go on vacations. It belongs to them.