a pronoun is a word that takes the place of a noun in a sentence. It can represent a person, place, thing, or idea without naming it specifically. Pronouns help avoid repetition in speech and writing.
Pronouns can be subjects (e.g., he, she, it, they) or objects (e.g., him, her, it, them) in a sentence. Possessive pronouns (e.g., his, hers, its, theirs) indicate ownership. Reflexive pronouns (e.g., himself, herself, itself, themselves) indicate that the subject and the object of the verb are the same. Relative pronouns (e.g., who, whom, whose, which, that) introduce relative clauses and connect them to the main clause. Demonstrative pronouns (e.g., this, that, these, those) point to specific things. Interrogative pronouns (e.g., who, whom, whose, which, what) are used to ask questions. Indefinite pronouns (e.g., anyone, everybody, nothing, several) refer to non-specific people or things.
She is my best friend. (Subject pronoun)
I gave the book to him. (Object pronoun)
This pen is mine. (Possessive pronoun)
The girl who sings is my sister. (Relative pronoun)
This is my favorite book. (Demonstrative pronoun)
Who is at the door? (Interrogative pronoun)
Everyone is welcome to join. (Indefinite pronoun)
be cautious with the use of 'who' and 'whom.' 'Who' is a subject pronoun, while 'whom' is an object pronoun. For example 'Who is calling? I don't know whom you met.' 'It's' and 'its' are often confused. 'It's' is a contraction for 'it is' or 'it has,' while 'its' is a possessive pronoun. Reflexive pronouns should only be used when the subject and the object of the verb are the same. For example 'She did it herself' (correct) vs. 'She gave it to herself' (incorrect if she is giving it to someone else). Remember that a pronoun should agree in number (singular/plural) and gender (male/female/neuter) with the noun it replaces.