To view and edit labels, go to the Labels section for the relevant type of content:
Each Labels section shows a list of labels that admins or agents have created.
By default, agents can add any label they want from the agent interface, but they will be prompted to choose from the list of existing labels.
You may want to prevent agents creating new labels: you can do this with the Agent Permissions system.
You can create labels from the admin interface so they show up on the list of choices. Simply click the +Add button to add a label.
You can also Setting label colors that will be shown in the agent interface.
You can delete a label by selecting it and clicking the Delete button. This removes it from all items to which it has been applied.