You can unsubscribe from the side menu --> "Manage User Account & Get More Data" --> then press the red button that says "Cancel Subscription".
Otherwise, you can unsubscribe here:
How to unsubscribe in the iOS App Store: https://support.apple.com/en-us/HT202039
How to unsubscribe in the Google Play Store: https://support.google.com/googleplay/answer/7018481/