1) If the subscription was paid by a bank card on the website or in a mobile app for iOS or Android:
Log in to the site using the account for which you subscribed, in the upper right corner click on your avatar, then "Settings", there is the "Subscriptions" section and the button next to "Cancel".
2) If the subscription is made in the iOS mobile app through standard Apple payment (in-app purchase):
Standard app "Settings"> iCloud (the topmost section)> Subscriptions> Find a subscription, go to it and click Cancel. More info:
https://support.apple.com/en-us/HT202039
3) If the subscription is made in the Android mobile app through the standard Google payment:
Standard app "Play Market" > click on your avatar in the upper right corner > Payments and subscriptions > Subscriptions. Find the subscription, go to it and click Cancel. More info:
https://support.google.com/googleplay/answer/7018481?hl=en&co=GENIE.Platform%3DDesktop