Yes, that's one way to say it, but that's more spoken language rather than written. In written French, we tend to put the question words at the start of the sentence: Où vont les Français en vacances? or even more formal with inversion: Où vont les Français vont-ils en vacances?
Yes, in spoken French that would be fine.
To put it more formally, just put the interrogative word at the start of the sentence and change the place of the verb: "Où vont les français en vacances ?".
Even more formal would be "Où les Français vont-ils en vacances ?"