Help kids shop responsibly by adding money to their Microsoft accounts, so they can buy what they want, without spending too much. Once you've added money to a Microsoft account it can be used to buy movies, games, in-app purchases, physical goods, or an Xbox subscription. This feature is currently only available on family.microsoft.com.
Go to your family group and sign in with your Microsoft account.
Find your child’s name. Select the name and then select Add money. If that option is not available, select Options > Spending > Microsoft account balance > Add money. There are several preset amounts to choose from. Your Microsoft account balance and gift cards are non-transferable to another person or Microsoft account. For more info, see Microsoft gift cards terms and conditions.
Require adult approval for buying to help avoid surprise spending when your child uses credit cards. Select your child’s name and then select Spending > Ask to buy. Turn on the option for Needs organizer approval to buy things.