Which is correct:
1) Who do you want to come with?
2) With who do you want to come?
3) Whom do you want to come with?
4) With whom do you want to come?
I heard using "whom" is formal and "who" is informal.
It was written if we use "who" the preposition can be only at the end of the sentence:
"who...with"
But if we use "whom" the preposition can be in the both places:
With whom...
Whom with...
But at the same time I read some information that having the preposition after the questioning word is informal like:
With whom... - formal
Whom with - should be informal
But it's a confusion.
The sentence "Whom ... with" is formal because of 'whom" but not "who" and informal because of "with" after the "whom".
Please, could you explain all of it to me?