Requesting a refund for unauthorized in-app purchases made by a minor on my device

Here's how to request an app or media refund from Apple (From: Request a refund for apps or content that you bought from Apple - Apple Support - see the article for more detail.) If you bought this in the EU from a third party, see: About purchases not billed through the App Store or the App Store’s In-App Purchase system - Apple Support instead.

1. Sign in to https://reportaproblem.apple.com

2. Tap or click "I'd like to," then choose "Request a refund."

3. Choose the reason why you want a refund, then choose Next.

4. Choose the app, subscription, or other item, then choose Submit.

Read this support article for information about how long it takes to receive a refund (if you are granted one), and how to check the status of a refund for apps or content that you bought from Apple --> Check the status of a refund for apps or content that you bought from Apple - Apple Support

Apple’s position appears to be that people need to be proactive with purchases, canceling subscriptions at least 24 hours before trials end, and ensuring that others are not able to make purchases on a user’s account. Note that if you allow—intentionally or not—another person access to purchasing on a device, or through Family Sharing if you are the Organizer, you are taking responsibility for things they do. Apple offers these proactive features:

On your device you can use Screen Time to prevent unintentional or unauthorized purchases from the App Store, in-app, and other Apple services. —> Use Screen Time to turn off in-app purchases on your iPhone or iPad - Apple Support

Also on your device, require a password for App Store and iTunes purchases —> Require a password for purchases in the App Store and other Apple services - Apple Support

Use Screen Time as part of parental controls on your child's iPhone, iPad, and iPod touch —> Use parental controls to manage your child's iPhone or iPad - Apple Support

If a child made this purchase on their device, consider activating Ask To Buy—> Approve what kids buy with Ask to Buy - Apple Support

Use Guided Access to permit a person to only use a single app —>

Lock iPhone to one app with Guided Access - Apple Support

You can try reportaproblem.apple.com. Know though that all purchases are considered final and that you are responsible for any purchase made on your account. It’s best to require a password before making a purchase and even better not to loan your device to anyone.

Linmos gave a good, detailed answer. But allow me to emphasize one point. By allowing someone else to use your device, you are authorizing any charges they incur. If you are going to do this regularly (as a grandparent, I am guilty of this), then your easiest solution is to require a password for purchases. This way, the minor would have to come to you for permission to make a purchase.

Also on your device, require a password for App Store and iTunes purchases —> Require a password for purchases in the App Store and other Apple services - Apple Support