If you're using Office 365 with a Microsoft Account, visit the Services and Subscriptions page to manage to the bill, cancel subscriptions, or install and download. If you no longer wish to receive the Cancel Office 365 subscription benefits, you can cancel the subscription or turn off Office 365 recurring billing.
Steps by steps Cancel Office 365 Subscription:
If your subscription allows it, click on Manage Installs to install office 365, or deactivate and remove devices from your list.
Click Personal info to edit your personal information tied to your Office 365 account.
Click Subscriptions to see any apps or services that your Office 365 plans include.
Click Security & Privacy to change passwords or contact preferences.
Click App permissions to manage the permissions of your Office 365 apps.
Click My Installs to manage your Office 365 apps.