Here you can see a list of all statuses that can be selected in the Status property of tasks and information about them. These statuses define the steps of the task life cycle.
You can manage the statuses in the list using the appropriate icon on the left side: Edit () or Delete (). The Move up () and Move down () buttons can be used to change the order of the statuses.
New statuses can be created by using the New task status link.
More resources can be found in Developer's Guide -> Modules -> Project management -> Overview.