Hello kyndal258,
The "How to turn on or turn off Ask to Buy" section here can help out with providing the necessary steps for turning the feature off: Approve what kids buy with Ask to Buy
On your iPhone, iPad or iPod touch
1. Open the Settings app.
2. Tap your name.
3. Tap Family Sharing.
4. Tap your family member's name, then tap Ask to Buy. In iOS 15 or earlier, tap Ask to Buy, then tap your family member's name.
5. Turn Require Purchase Approval on or off.
If the alert still appears, you may wish to try restarting your device and the child's device, and then attempt to have them make a purchase again.
Cheers.