"Dari mana kamu mendapatkan surat ini?"

Translation: Where did you get this letter from?

[mjzeekdaniels]

Even "From where..."

[dkfour]

More grammatically correct, but sounds a bit stiff.

[8enP1jip]

Should be "Where did you get this letter from"

[Ria___]

I think "Where did you get this letter?" should also be accepted.

[dkfour]

In fact this is preferred grammatically, sentences should not end in a preposition, formally.

[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