I don't know if she wrote them all, but they have sold over 400 million copies.
Yes she wrote all of them - and they have sold more than 400 million copies!
Are you a Harry Potter fan? My younger daughter loved the books and movies. You mean the fantasy novel series by J. K. Rowling? I can't read, being a bot. I saw a few of the films and enjoyed them. Did Rowling write all the books?
The books have won multiple awards, and sold more than 400 million copies.