Reported Questions

Reported questions are one form of reported speech.

direct question	reported question
She said: "Are you cold?"	She asked me if I was cold.
He said: "Where's my pen?"	He asked where his pen was.

We usually introduce reported questions with the verb "ask":
He asked (me) if/whether... (YES/NO questions)
He asked (me) why/when/where/what/how... (question-word questions)

As with reported statements, we may need to change pronouns and tense (backshift) as well as time and place in reported questions.

But we also need to change the word order. After we report a question, it is no longer a question (and in writing there is no question mark). The word order is like that of a normal statement (subject-verb-object).

Reported YES/NO questions

We introduce reported YES/NO questions with ask + if:

direct question	She said,	"Do you like coffee?"
reported question	She asked	if I liked coffee.

Note that in the above example the reported question has no auxiliary "do". But there is pronoun change and backshift.

Note that we sometimes use "whether" instead of "if". The meaning is the same. "Whether" is a little more formal and more usual in writing:
They asked us if we wanted lunch.
They asked us whether we wanted lunch.

Reported question-word questions

We introduce reported question-word questions with ask + question word:

direct question	He said,	"Where	do you live?"
reported question	He asked me	where	I lived.

Note that in the above example the reported question has no auxiliary "do". But there is pronoun change and backshift.

Remember that there are basically three types of question:

1.-YES/NO questions: Do you want tea?
2.- Question Word questions: Where did you drink tea?
3.- Choice questions: Do you prefer tea or coffee?

Reported choice questions have the same structure as Reported YES/NO questions. Questions with the verb BE always have a different structure: Was the tea cold? Where is my tea? You can see all these differences in the examples below.

Look at these example sentences:

	direct question	reported question
YES/NO questions	I said: "Can I help you?"	I asked if I could help her.
	She said to us: "Did you feel cold?"	She asked if we had felt cold.
	He said: "Are your hands cold?"	He asked whether my hands were cold.
question-word questions	He said: "Where are you going?"	He asked me where I was going.
	He said: "Why didn't you say something?"	He asked me why I hadn't said anything.
	He said: "When will they come?"	He asked when they would come.
	He said: "Who has seen Avatar?"	He asked me who had seen Avatar.
	He said: "How much might it cost?"	He asked me how much it might cost.

taken from:

https://www.englishclub.com/grammar/reported-questions.htm