1) What is a wh-question?
A wh-question is a question that starts with a wh-word, such as 'Who', 'What', 'When', 'Where', 'How', 'Which', 'Why' or 'Whose'.
Examples:
Who is your favourite actor?
Where is the dog?
2) How to form a wh-question
We usually form a wh-question with 'to be', an auxiliary verb or a modal verb before the wh-word.
Examples:
Where is the coffee machine?
What did Susan build?
When will she arrive?
3) How to answer a wh-question
We don’t use 'Yes' or 'No' to answer a wh-question, we need to give information to answer it.
Examples:
Where is the coffee machine?
It is in the kitchen.
What did Susan build?
Susan built a castle.
When will she arrive?
She will arrive tomorrow.