A question is a request for information, which can be made in syntactically non-interrogative clauses:
I wonder what your name is.
I wonder whether you would close the door.
Tell me what your name is! though this gets close to a request for services/action
And we call these questions because of the intonation. However, these are two distinct concepts. An interrogative isn't always a question, and vice versa.
There's a distinction here between form and function.
The grammatical form that the clause takes determines a number of things, one of them being the grammatical mood - the interrogative is one of these, typically marked in English by things like subject-auxiliary inversion, for instance.
You have written a good answer
Have you written a good answer?
Intonation can play a part, but it's important to note that written language is not a representation of spoken language, and so if we mark a clause as interrogative with a declarative syntax, we're clearly coercing a reading that would not be made. It's an attempt to import features of spoken language into the writing.
You're studying.
You're studying?
The function that a sentence can perform is to ask a question - generally, by this, we mean a request for information (as distinct to a request for services, which we call imperatives (grammatically) or demands (functionally).
I wonder what your name is.
Even said with a declarative tone, it would be clear that I am asking for your name, if I said this in conversation.
Tell me what your name is!
Although this might be classed as an imperative (as it comes very close), it's really still asking for your name.
Interrogatives that aren't questions
Usually these are rhetorical.
It's a bit sunny, isn't it?
There's no doubt, there's no question - if it's a hot, clear day and I say this, then it's small talk and a comment on the temperature, not a request for information. (On the other hand, if it's a cold, cloudy night, someone check me for signs of stroke.)
Could you please close the door?
Here's something that's a request for services, rather than information. I'm not really asking you if you're capable of closing the door (although it's a common joke to take it as such). I'm asking you to do it.
tl;dr These are different, albeit related, concepts. Don't conflate them. Edit the tag wikis (Maybe.)
Question:
This tag is for questions about about requests for information.
Interogative:
This tag is for questions about the grammatical form.