If you have an iCloud subscription, you will receive a monthly bill from Apple, check your email box.
You pay monthly for iCloud storage.
Check -> Go to -> Settings -> your name -> iCloud -> if you see 50 GB (or 200 GB or 2 TB) then you have an iCloud subscription.
or perhaps Apple Music?
Apple Music subscription is $9.99/month
Check for sure the following Apple articles:
View your purchase history for the App Store, iTunes Store, and other Apple media services
View your purchase history for the App Store, iTunes Store, and other Apple media services - Apple Support
How apps, content, and subscriptions from Apple are billed
How apps, content, and subscriptions from Apple are billed - Apple Support