Translation:What did you make?
In normal spoken Japanese, you would know from the context. There isn't anything in the actual sentence itself that would identify it, so since there is no context for the sentence, "what did you make?" and "what did he/she make?" need to be acceptable translations if they aren't in there already.
The verb is 作る (つくる). It's in polite form: つくります, and conjugated in the past tense: つくりました. There's two parts to this sentence: "何を", meaning "What", being used as the direct object of the sentence, and "つくりました", the polite past tense of "make", and finally か to mark a question. "What did you make?".
Sorry for asking something that is dumb and probably obvious, but why do we need the か at the end? Maybe I don't understand it since I'm looking from the English standpoint where we already have the "what" (何) in the beginig so I take it for granted that it is a question and so I don't see a need for the symbol marking the sentance as a question (か), I hope if it's just something as simple as that you won't get mad at me for wasting your time :)