Unauthorized payment

Make sure it's not a Phishing Scam --> Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

If however it is an actual charge you don't recognize, see this link --> If you see "apple.com/bill" or an unfamiliar charge on your statement - Apple Support

Check your purchase history—>See your purchase history for the App Store or iTunes Store - Apple Support

How did you find out about this payment? If it was by an email it may have been a scam—>Identify legitimate emails from the App Store or iTunes Store - Apple Support

And if you saw it on your bank statement or website—>If you see "apple.com/bill" or an unfamiliar charge on your statement - Apple Support

If, after checking all of these, if it is an actual purchase either you authorized it, someone you share an Apple ID with made it, or your Apple ID has been hacked. For that last possibility see—>If you think your Apple ID has been compromised - Apple Support

Are you sure it is from Apple? Have you checked your bank statement?

Should be this case, start here:—> If you see "apple.com/bill" or an unfamiliar charge on your statement - Apple Support

Regards

Giulio