Final answer:
Amazon SQS uses a queue URL as an identifier for each created queue, which is required when performing actions on the queue.
Step-by-step explanation:
The identifier assigned by Amazon SQS to each queue you create is called a queue URL. This URL includes the queue name and other components that Amazon SQS determines. Whenever you want to perform an action on a queue, such as sending messages or retrieving them, you provide its queue URL.