Hello Hotaru, the best way to put this question would be: Kindly write your address for me to send you the original. Or Please write the address for where you would like the original sent. It is usually better to finish the sentence with a verb or a noun. You don't need to include 'ask you' because it is really a direction, not a question. Let me know if you need any more explanation :) Hope this helps!

It's not the preposition at the end, but the sentence in general. "Kindly asking you to indicate where I should send the original." This is OK, but because there's no subject it sounds either colloquial or curt. If this is for a business email, we can offer a more professional and polite phrase. For your original question, the English "where" can stand for both где and куда.

Kindly ask you to write me your address to send the original to. >Kindly ask the person for the address that I should use to send the original .