Here are some simple, basic rules about pronouns:
Pronouns are words used to substitute for nouns
All pronouns are either singular or plural.
Singular pronouns replace singular nouns (Replace Jeff with “he” or Marcy with “she”)
Plural pronouns replace plural nouns The children (noun) replaced with “they” the pronoun.
All pronouns ending with one, thing, or body are singular (Everyone, Everything, Everybody)
Example: Everyone is excited about graduation! Everything is going to be fine. Everybody has the right to say no if they want to.
Either and neither are singular.
Example: Neither parent is going to be happy with your behavior. Either Joan or Linda is going to meet you at the meeting.
Subject pronouns are used when the pronoun is the subject of the sentence.
Example: ___ did a good job.
I, he, she, we, they, who, whoever, etc.,
There are also object pronouns, known more specifically as direct object or indirect object, Object pronouns include me, him, herself, us, them, themselves.
Jackie saw him at the game.
Him is the direct object of the verb saw.
Give her the book.
The direct object of give is book, and her is the indirect object. Indirect objects always have an implied to or for in front of them: Give [to] her the book. Do [for] me a favor.
When you have pronouns linked with nouns and the word “and”, read the sentence removing “and her friend” and see if the sentence makes sense.
Incorrect: Her and her friend came over.
If we remove and her friend, it becomes grammatically incorrect: Her came over.
Correct: She and her friend came over.
Incorrect: I invited he and his wife.
If we remove and his wife, it becomes grammatically incorrect: I invited he.
Correct: I invited him and his wife.
Incorrect: Bill asked my sister and I.
If we remove my sister and, it becomes grammatically incorrect: Bill asked I.
Correct: Bill asked my sister and me.