A queue is a list of items or tasks that need an action performed on them. These can be thought of as a list of requests. Items in a queue are generally listed in the order in which the request was made. A simple example is a print queue, in which a particular user on the system is in charge of printing labels, so other users make a request to that user. The queue is filled with requests to print labels. Queues are often used to represent various real-world tasks that must be completed. Sometimes, the actions are performed all within the application itself.
In addition to a list of requests, the queue contains buttons for various actions that need to take place. These buttons can be as simple as printing labels, as mentioned above. Once a label is printed, the item is removed from the queue. They can also contain more complex functions, like performing an action and sending a notification to a user or group. Perhaps the item gets moved to a different queue when a specific action is performed. These are just some of the possibilities.
Queues are managed through Control Panel, Queues within the application.