how do i recover the apple id for my child?

I created an apple ID for my daughter at the end of the last school year so she could save some of the items from her Mac-book. She wants to download those items to this years school computer, also a Mac, but her father lost the papers that have her email, Apple ID, and I cloud address. I don't remember the information but i kow i put my email as the recovery email and i thought it was all under family sharing, but now my computer is telling me that family sharing is off. Since we have a PC and I-pad, we couldn't download directly to them. How do I recover her i could address and Apple ID without the email address?