Unknown charges from App Store in my credit card bill, what to do?

See if you can find it here, which should specify each charge to your Apple ID account:

View your purchase history for the App Store and other Apple media services - Apple Support

Note that Apple may bundle several products and services in one charge, in some countries.

If you have Apple Family Sharing with Purchase Sharing active, then toggle to include those charges as well.

If someone else has access to this payment method, then check with them as well.

If the above doesn’t list it, then please detail the description on your statement, for deeper inspection.

There have been scamming attempts to charge users in a way that looks very similar to Apple’s charges. If that is what happened, then you’ll have to contact your card issuer about fraudulent charges.

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

Identify legitimate emails from the App Store or iTunes Store - Apple Support

Billing and subscriptions - Official Apple Support

Also see these two outside article on the subject:

https://www.foxbusiness.com/personal-finance/credit-card-statements-scam-charge

https://toughnickel.com/scams-fraud/Apple-iTunes-866-712-7753-Scam

Note that the second article is only a few months old.

We had the same scenario happen but the charges were from another sector, a major US department store chain with whom we'd not done business since long before the Internet was a thing. Our card service, AMEX, confirmed the charges as bogus, cleared the debt, and issued Mrs AJ a new card number. IT was her number the was compromised. That stopped any more such charges. The retailer whose name was on the charges could have done nothing because they had no records of charges criminals make.