Every page on Practice has a filter tab with the option to sort or filter the objects you're looking at whether it's schedulers, forms, packages, or even products!
A client cannot use an inactive object. You might even consider it a "draft" because it exists within your account, but is not active.
In some cases an object can be automatically moved to inactive. For example, when your calendar is disconnected, schedulers become inactive. Or, if a scheduler is deleted within a package, the package will become inactive until you reactivate it.
To view inactive (or toggle the active) objects, use this drop-down: