"Dari mana kamu mendapatkan surat ini?"

Translation: Where did you get this letter from?

[mjzeekdaniels]

Even "From where..."

[SherleneKl]

Grammatically correct is "From where did you get this letter?" You don't end a sentence with a preposition.

[ZoeVincent5]

Where DID right?

[Speedy12846]

It should be where did you get this letter from and not where do you get this letter from.

[wolfe.mcbr]

This sentence doesnt have any tense markers, so either should be fine