Subject questions

Here's a question from Jesús which you might have been wondering about yourselves:
Hello David, I have a problem when I want to write one sentence because I have read the next sentence:

Who thinks uniforms are a good idea, but doesn't likes her uniform?

Is a question about a text where some people talk about your work uniforms. My problem is the verb ("thinks") and its use with 's'.

And here's my reply:
Hi Jesús,
This is a very good question. When asking questions, we only use the third person s after the verb if the question word (Who, What, What + complement) is the subject of the question (and the tense is the present). This are called ‘subject questions’. (If you google it you’ll find several examples).

Subject questions are not typically used with when, how and why as these question words usually require another subject:
When does Christmas season begin?

Examples of subject questions:

Who lives in Móstoles?

What actor plays Aquiles in the film, “Troy”?

Who has a pet?

What happens after the four “cuartos” on New Years’ Eve?