You can subscribe to Apple services like Apple Music as well as in-app services from various third-parties. You can see all of your reoccurring subscriptions in either iTunes on your Mac or in Settings on your iPhone or iPad. From there you can change the subscriptions to other plans offered, or cancel them. In many cases you can cancel a subscription but still use it until the next renewal date.
See Also: https://support.apple.com/en-us/HT202039