Adjective gives more specific about noun or pronoun.
It may answer any of three specific questions about the noun(s) or pronoun(s) : what kind?, which one(s)? or how many?
Adjectives are also called modifiers because they modify the image of noun we have in mind. For example if we say Car which is noun, It is very general term now if we specify more clearly white BMW car it gives more clear picture of the same.
Articles are kind of Adjectives which give information about Nouns
They look like proper nouns because they are captialized but they are modifying nouns, and therefore are called adjectives.
It will answer the question what kind or which one? about the noun.
For Example : Darjeeling Tea is very famous around the world.
Now, kind of Tea is Darjeeling (which is a place in India). Here, it is Proper Adjective.
A possessive adjective ("my," "your," "his," "her," "its," "our," "their") is similar or identical to a possessive pronoun; however, it is used as an adjective and modifies a noun or a noun phrase.
The demonstrative adjectives "this," "these," "that," "those," and "what" are identical to the demonstrative pronouns, but are used as adjectives to modify nouns or noun phrase.
An interrogative adjective ("which" or "what") is like an interrogative pronoun, except that it modifies a noun or noun phrase rather than standing on its own.
An indefinite adjective is similar to an indefinite pronoun, except that it modifies a noun, pronoun, or noun phrase.