Family sharing
How do I turn off app permission on a child’s iCloud account?
You can’t turn it off for free apps only.
With Ask to Buy and Family Sharing, whenever a child initiates a new purchase or free download, a request goes to the family organizer. The organizer can review the item and approve the purchase or decline the request right from their own iPhone, iPad, or iPod touch. For example, this could be a request for items in the iTunes, Apple Books, or App Store, In-App Purchases, or iCloud storage.