Shortcut menu commands can appear on a Class Definition to create new subscriptions, or manage existing ones, for the selected Class definition.
Shortcut menu commands can appear on an object to create new subscriptions, or manage existing ones, for the selected object.
Administration > Subscription Menu is used to manage existing subscriptions for all objects, classes, and users.
You can only create new subscriptions via this route if the object or Class Definition already has a subscription.