Charge on my card says apple bill cupertino ca - what is it?

Search your email for "Your receipt from Apple". They email a receipt for every charge, with the item and the Apple ID it was bought on. If none match the amount and date, it was bought on an Apple ID that isn't yours, which tells you something too.

That's how every Apple digital purchase shows on a statement: App Store, iCloud storage, Apple Music, in-app purchases, subscriptions through your Apple ID. On an iPhone go to Settings > your name > Subscriptions to see what's recurring, and Settings > your name > Media & Purchases > View Account > Purchase History for one-off buys. Match the amount and date. If nobody in the house recognises it, check if a family member's device or Family Sharing is using your card, then report it through Apple's report a problem page and tell your bank.