Q: Permission for family purchases

I looks like it goes to your notifications: Request and make purchases with Ask to Buy - Apple Support

-AJ

Approve or decline a request

If you're the organizer, you can use these steps to make or decline the purchase from your iOS device or Mac:

1. Open the notification to see the item that your family member wants to get. (See your notifications on your Mac or iOS device.)
2. Approve or decline the purchase.
3. If you approve, you need to sign in with your Apple ID and password to make the purchase.

After it's purchased, the item is added to the family member’s account and shared with the rest of the family group. If a family member downloads a previous purchase again, downloads a shared purchase, installs an update, or uses a redemption code in the store, the organizer won't get a notification.If you decline the request or don't make the purchase, it will be deleted after 24 hours, and the child will need to make the request again.

Choose another approver

The organizer can give another parent or guardian in the group permission to manage Ask to Buy requests. Only one adult needs to manage each purchase, and after it's done, the purchase is final.

• On your iPhone, iPad, or iPod touch, tap Settings > iCloud > Family, tap your family member, then tap Parent/Guardian.
• On your Mac, choose Apple menu > System Preferences > iCloud, select your family member, then select Parent/Guardian.