The queue structure is a simple structure like the stack.

The difference from the stack is that the first elements to enter the queue get processed first.

That is, service requests get added to the end of the list. That is why, it is also defined as First In First Out (FIFO) storage.

The queue is an ordered waiting list.

Those requesting a specific service enter an ordered list to get that service.

The first element to get added to the list gets served first. (First-come first-served "FCFS")