First we have to know the deinition of personal pronoun.

Personal pronoun are pronouns that to a specific person or thing in a sentence and can be divided into two groups: nominative and objective.

Nominative personal pronouns can act as the subject of a sentence ( I, you, he, she, it, we, they). for example:

I went to the store after work.   You should not go to class if you are sick.

Objective personal pronouns, on the other hand, act as objects of a sentence ( me , you, you, him, her, it, us, them).

For Example:

Fidel came out with Daniela and me.             Melissa really likes him.