You can turn off auto-renewal of your subscription in the "Billing" section of your account settings. This will stop your subscription from renewing when the next payment cycle occurs.
To find this, first click your avatar in the top right and select "My Account".
With your account settings open, navigate to the "Billing" page. From here, you can manage your subscription with the "Amend subscription" button.
This will open the subscription settings where you can cancel your subscription.
After which your account will be deactivated and then fully deleted (including all your documents and bundles) after an additional 30 days. For more information on our account deactivation policy, please see here.