What's the difference between them? and when do we use "What he does" and "What does he do"?
What he does
What does he do?
What he does is an incomplete sentence. It can not stand on its own. It may be part a sentence or a part of an indirect question.
For example, you may ask someone what does he do?
The expected answer may be: He is a teacher.
If you want to be polite , you may ask an Indirect question such as:
Do you know what he does?
The expected answer might be:
Yes. I know what he does. He is a teacher
What+ helping ver b+ subject+ do( main verb)
Here helping verb follows the wh-word.
The second part of a complex sentence or an Indirect question is what he does
The structure is:
What + subject+ main verb( does)
However, sometimes What he does? may be question with a rising tone in speech or a question mark in the end in writing?
What he does?
Here is two links which help us to know the differences.
What is mostly used for two things:
asking for information specifying something.
"what is your name?"
asking for repetition of something not heard or confirmation of something not understood.
"what? I can't hear you"
the thing that / things that (used in specifying something).
"what we need is a commitment"
(referring to the whole of an amount) whatever.
"I want to do what I can to make a difference"