The use of has or have to answer question

Question

Which one is correct out of the sentences below?

Has your children been to the US ?

or

Have your children been to the US?

Answer 1

Adding to Timinycricket's answer, please note that your concern is about subject-verb agreement.

"Has" is the singular form of the verb, while "have" is the plural.

Considering that children is a plural noun, you should use "have", not "has".

Answer 2

If it is singular then it would be:

Has your child been to the US?

If more than one it would be:

Have your children been to the US?