누가 상자를 보낼 것입니까? Subject-object-verb.
In Korean it doesn't really matter, since you can tell what the role of every word is by the particles (-를, -가).
You can still switch it up and it will still make sense. The emphasis is probably on "who" so it would make sense to put 누가 in the second position.
누가 箱子를 보낼 것입니까?
누가 漢字를 쓸 것입니까?
why isn't it who will I send the box to?
There is no 에게, no one to receive the box.