Which is grammatically correct - where you come from or from where you have come?

Answer 1

Yes. Many people think there is a rule against ending a sentence with a preposition. If that were true, then it would not be grammatically correct to say, "Where are you from?" However, most grammarians do not think there is such a rigid rule. Although you could avoid the preposition at the end by saying "From where are you?", that is not how people actually speak and write English. So most would say that it is perfectly correct to say, "Where are you from?"

Answer 2

Both forms are correct, but the first is better. It uses natural English grammar, while the second uses stilted Frenchified grammar. The mistaken notion that an English sentence should not end with a preposition comes from the study of Latin, which at one time was considered somehow more "correct" than English.