WH questions are used to ask for specific information.
These are the words that begin with "wh-" (except for how):
Seek specific information: Unlike yes/no questions, WH- questions require more than a simple "yes" or "no" answer. They prompt a more detailed response related to the WH- word used.
WH- word + auxiliary verb + subject + main verb + ...?
Sometimes, the WH- word itself is the subject of the sentence. In these cases, the structure is slightly different:
In these cases, no auxiliary verb is needed before the subject because the WH- word is the subject.