These are we called by WH-QUESTION and we use it for interrogative form

why => asking for the reason 
E.g : Why you didn’t come for the party ?

what => asking for noun, condition, demonstrative noun and object ( adverb )
E.g :

  • what is your name ? ( pronoun )
  • what is that ? ( demonstrative noun )
  • what time is it ? ( adverb/object )

when => asking for condition usualy for time, date, day and year
E.g : when will you come ?

where => asking for place
E.g : where do you want to hang out ?

who => askinh for pronoun as a pronoun ( can be subject and object pronoun )
E.g : who is standing next to you ?

which => asking for decision
E.g : which book do you like to read ?

whom => asking for pronoun ( only for an object pronoun )
E.g : whom do you go with ?

whose => asking for possesive pronoun
E.g : whose book is that ?

how => asking for condition
E.g : how do you go to school ?

What
🥀 Asking for information about   
      something.
       E.g : What is your name?
🥀 Asking for repetition or
        confirmation.
        E.g : What? I can’t hear you.
                 You did what?

What….for
🥀 Asking for a reason, asking why.
       E.g : What did you do that for?

When
🥀 Asking about time
       E.g : When did he leave?

Where
🥀 Asking in or at what place or position.
       E.g : Where do they live?

Which
🥀 Asking about choice
        E.g : Which colour do you want?

Who
🥀 Asking what or which person or people
       (subject).
       E.g : Who opened the door?

Whom
🥀 Asking what or which person or people
       (object)
       E.g : Whom did you see?

Whose
   🥀 Asking about ownership
          E.g : Whose are these keys?
                   Whose turn is it?

Why
🥀 Asking for reason, asking what…for.
        E.g : Why do you say that?

Why don’t
🥀 Making a suggestion
        E.g : Why don’t I help you?

How
🥀 Asking about manner
        E.g : How does this work?
🥀 Asking about condition or quality
        E.g : How was your exam?

How + adj/adv
🥀 Asking about extent or degree
        E.g : See example below.

How far
🥀 Distance
        E.g : How far is Pattaya from Bangkok?

How long
🥀 Lenght
        E.g : How long will it take?

How many
🥀 Quantity (countable)
         E.g : How many cars are there?

How much
🥀 Quantity (uncountable)
        E.g : How much money do you have?

How old
🥀 Age
        E.g : How old are you?

How come(informal)
🥀 Asking for reason, asking why
        E.g : How come I can’t see her?