A To cancel the Premium Membership, you need to do it by yourself.
Please refer to the links below.

App Store version:
https://support.apple.com/en-us/HT202039

Google Play version:
https://support.google.com/googlenews/answer/7018481?hl=en

Huawei AppGallery version:
https://ibispaint.com/lecture/index.jsp?no=26#huawei

Microsoft Store version:
https://support.microsoft.com/en-US/topic/how-to-cancel-your-microsoft-subscription-cca7a013-10c7-48ba-9b46-b931e7431826

If you do not cancel your Premium Membership at least 24 hours (in case of Windows, 48 hours) before the last day of the subscription period, it will be automatically renewed and the fee will be charged.
Please note that same goes for the free trial period, if you do not cancel it at least 24 hours (in case of Windows, 48 hours) before the last day of the period, it will be automatically renewed and the fee will be charged.