If you prefer a somewhat more detailed and decriptive list that includes a few reasons and solutions not mentioned in the article posted earlier:
The support article If you see 'apple.com/bill' on your billing statement - Apple Support explains how you can check your iTunes and App Stores purchase history, cancel subscriptions, and track possible sources of unrecognized Apple charges you may see on a bill. These may be purchases by family members if you are an organizer of a Family Sharing group, or possibly a second Apple ID you use. The article also provides a specific link for contacting Apple if you cannot trace the source of charges. If you use Apple Card you may find this document helpful too ➞ If you see an Apple Services charge you don't recognize on your Apple Card - Apple Support
Also note this service: View your App Store and iTunes Store purchases directly from your financial institution - Apple Support
"When you sign in to your financial institution website or mobile app and view your recent purchases from the App Store, iTunes Store, Apple Books, or for Apple Music or iCloud services, you may see an option—such as View Receipt—that allows you to view more details about your transaction."
Other possibilities to consider (not all may apply in your situation):
● Purchases can be made with your ID if your Apple ID is compromised (read what to do ➞ If you think your Apple ID has been compromised - Apple Support ) or somebody else has access to your device (require a purchase password as explained in this article ➞ Require a password for App Store and iTunes purchases - Apple Support ).
● If you only see a charge in emails or texts that are not official Apple receipts, it is likely phishing attempts (see the article: Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support ).
● If you are absolutely certain neither you, nor Apple, nor a Family Sharing member can account for a charge and it ONLY appears on a bill for a charge card you alone control, you may have been the victim of card fraud. Contact your financial institution.
● Small amounts of ~$1 may be an authorization hold that will be refunded (pending charge ➞ How apps, content, and subscriptions from Apple are billed - Apple Support ).
● Unanticipated amounts may be grouped charges ( How apps, content, and subscriptions from Apple are billed - Apple Support ).
If a purchase is listed in your purchase history and you want to ask for a refund, read this article about how to request a refund for apps or content that you bought from Apple ➞ Request a refund for apps or content that you bought from Apple - Apple Support
If a Family Sharing member made the purchase then you need to discuss this with that person. They would have to initiate any refund request.
If a reporting a problem request is unsuccessful or you have another issue you can also speak with Apple ➞ Choose your country or region - Official Apple Support Select your country, then a product.
or:
Contact Apple for support and service ➞ "See a list of Apple phone numbers around the world."
Click here ➞ https://support.apple.com/HT201232
