Unless you cancel at least 24 hours before the end of the free trial, you will be automatically charged a price indicated on the payment screen or/and Apple’s payment pop-up screen for a chosen subscription period.
The subscription renews automatically at the end of each period (each week, month, 6 months, year, or otherwise) until you cancel.
Payment will be charged to your iTunes & App Store/Apple ID account ("Account") at confirmation of purchase (after you accept by Touch ID, Face ID, or otherwise the subscription terms on the pop-up screen provided by Apple) or after the end of the free trial.
You can cancel a free trial or subscription anytime by turning off auto-renewal through your Account settings.
To avoid being charged, cancel the subscription in your Account settings at least 24 hours before the end of the free trial or the current subscription period.
You alone can manage your subscriptions. Learn more about managing subscriptions (and how to cancel them) on Apple support page. Note that deleting the app does not cancel your subscriptions (however, if you use Apple’s IOs 13 or later IOs versions, Apple provides you with a convenient way to manage subscriptions when you delete an app).
If you purchased a subscription through the Apple App Store and are eligible for a refund, you'll have to request it directly from Apple. To request a refund, follow these instructions from the Apple support page.
Please make a screenshot of this information for your reference. This may help you to control your subscriptions.