When a sentence is a question where is the subject located?

The subject is before the main verb and after a be or auxiliary verb.

Questions with question Words:

present simple question -- Where do they live?

present simple question -- What does she do?

past simple -- Where did you go.

present continuous -- Where are you living?

present perfect -- Who have you told?

For yes/no questions the subject is after the auxiliary or be verb:

present simple -- Do you like ice cream? Are youhappy?

past simple -- Did you see her? Was she happy?

present continuous -- Are they coming tomorrow?

present perfect -- Have you been to Ekatahuna?