Adjectives describe nouns or pronouns.

Type Examples
articles a, an, the
demonstrative this, that, these, those
possessive my, your, his, her, its, our, their
numerical two, first
indefinite all, none, some, any

Difference between adjective and pronoun

Adjective Pronoun
Which article did you write? Which did you write?
I wrote this article. I wrote this.