Formal:
* Où êtes-vous allé(e)? (Where did you go?)
* Où avez-vous été? (Where have you been?)
Informal:
* Où es-tu allé(e)? (Where did you go?)
* Où as-tu été? (Where have you been?)
* Tu es allé(e) où? (Where did you go?)
More specific:
* Où es-tu allé(e) en vacances? (Where did you go on vacation?)
* Où es-tu allé(e) ce week-end? (Where did you go this weekend?)
Note:
* You need to use the correct gender agreement for the verb "aller" (to go). "Allé(e)" is the past participle, and it agrees in gender with the person you are asking.
* "Tu" is used for the familiar form, while "vous" is used for the formal form.
Hope this helps!