"Who is using the car today?"
Translation:Ki használja ma az autót?
Most of the question words have to be followed by a verb (if there's one). All of the word orders are correct here, as long as you think of "ki használja" as one unit.
The only question words that don't follow this rule are the ones that refer to a noun instead of the action. "Milyen" and "melyik" are the only ones I can think of right now: "Milyen házat akarsz?" -- "What kind of house do you want?; "Melyik labdát választottad?" -- "Which ball did you choose?"
And also "kinek"/"minek", if they mean "whose": "Kinek a kutyája ül ott?" -- "Whose dog is sitting there?"