Difference between Formal and informal question?

Question

There are two questions:

A- How come you're a reporter?

B- How is it that you're a reporter?

Why A is informal and B is formal?

And I found that difficult to know that making the Informal question into formal question especially there are no rules.

Answer 1

These are not formal and informal questions.

A- How come you're a reporter?

This is asking how it came about that you are reporter? The speaker wants to know how, or maybe why, you became a reporter.

B- How is it that you're a reporter?

This is asking how it is possible that you can be a reporter. The speaker cannot understand how a person like you can be a reporter- suggesting maybe that you are incompetent, or that there are aspects of the job that you might not be able to deal with.

Answer 2

The second question is not formal; I don't think a native speaker would use it at all, it seems awkward. In general, though, formal language does not use contractions. However, even if we expand the contractions to get "How it is that you are a reporter?" that does not sound natural.

You might mean "How is it that you are a reporter?"

Answer 3

direct and indirect are same as formal and informal question

Direct questions are the “normal” questions that we can ask to friends, family members, and people who we know well.

Example of a direct question: “Where’s the bathroom?”

Indirect questions are a little more formal and polite. We use them when talking to a person we don’t know very well, or in professional situations, and their form is a little different.

Example of an indirect question: “Could you tell me where the bathroom is?” Phrases for Indirect Questions

Could you tell me…
Do you know…
I was wondering…
Do you have any idea…
I’d like to know…
Would it be possible…
Is there any chance…

Answer 4

"How come" seems to be a contraction -- shortening 'How has it come to be that...you are a reporter?' Few people really talk like this latter statement; and few people would write 'how come' other than in a casual way.

So, like many contractions, yes -- 'how come' is considered colloquial or less formal than the full statement.

'How come' can often be replace by 'why' for a simpler sentence.

Although 'why' feels to inquire more about about logic (Why did you choose reporting as your career when other fields are so much more lucrative?) rather than passage (How is it that you came to be a reporter despite having studied biology in school?).