Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Log into your Microsoft account on this link:
https://go.microsoft.com/fwlink/?linkid=2323737
On that web page, you should see the option to Cancel or Upgrade or Cancel your subscription and form there, you can cancel the subscription.
Also, while managing the subscription, be sure to disable the Recurring billing on the subscription to ensure no further payments are deducted from your account.