If your household doesn’t have a payment method set up, child accounts now have the option to ask their parent to approve or deny purchases on the Play Store. Your kids can send you an “approval request” for you to buy them paid apps or in-app purchases in games. If you approve a request, Google will ask you to pay for the item using your payment method, which will not be shared with any other family members. And once you pay for it, it’ll immediately become available on your child’s Google account.
This gives you a way to buy digital items without adding your credit/debit card to your kid’s account, or sharing it as a family payment method. Using this, you’ll be able to keep your payment method to yourself while still buying the occasional game or in-game item.
Google has a new support page outlining the setup process. You’ll need to set yourself up as the manager in a family group before continuing.
Source: Google