Use “How many” to ask the number of people, animals, countable objects, etc.
Example:
Kris Evan : How many pens do you have?
Kevin Warhol : I have two pens.
Remember:
The words ‘how many’ are always followed by noun in plural forms. See the above examples. To answer the questions with ‘how many’, we usually use the verb ‘have’ for plural subjects or ‘has’ for singular subjects.