I have shared my Premier with my daughter. She has her own iCloud storage and has been paying for it. Suddenly, it is now being charged to my account. How can I stop this and let her continue to pay for her iCloud storage?

When you create a family share, the family organizer becomes responsible for all purchases. She can pay her own if she has gift cards on her Apple ID as those will be charged first.

You shouldn’t have to turn off purchase sharing when you go to purchase sharing settings, at the top should be, shared payment methods I think you should be able to click on it and disable your card, I’ve never done it so I don’t know if that’s actually possible but it should be