What are Japanese question?

Well your question doesn't really make sense. I mean... if you're asking how to make a question, a question usually ends with ka （か）and a regular period. (。)
And then there's the where, when, what, etc. part.. (I've used a couple of examples)
When: Itsu　いつ

Where: Doko　どこ
Ex. Where is Jon?
Jonwa(Jon is) doko(where) desuka?
ジョンはどこですか。

Why: Nande　何で

How much: Ikura　いくら
Ex. How much is this book for?
Korewa(This) hon(book) ikura(how much) desuka?
これは本いくらですか。

What: Nan or nani 何
Ex. What is your name?
Onamaewa(your name) Nan(what) desuka(desu is like.. to "be" and ka states a question)
お名前は何ですか。

When you read these and separate them apart, it's a little weird sounding, but that's the way it is. Japanese is written in a different order than English. We go SVO and they go SOV. We start with the Subject (John) then the verb (eats) ending with the object (an apple). They'd switch eats with apple. Which makes it Jonwa Ringo o tabemasu. じょんはりんごを食べます。

Sometimes it could end with desu, imasu, imasen, tabemasu, etc. But when you're asking something, you always add a 'ka'.

Although, if all this was just a waste of time, and you just wanted to know how to say question in Japanese, that's mondai. 問題。