In a typical Salesforce Implementation project, we create queues for different Used cases. Lets take a used case, where a Lead comes in to a Queue and gets validated before being assigned to an User. Follow the below steps in Salesforce Lightning

In Salesforce Lightning, Go to Setup by clicking on the Gear icon in Top right corner.
Enter "Queue" in Quick Find search box
Now Click on Queues under Users
Click on "New" in the Queue setup; you will see the below page.
Fill in the mandatory fields and select the object and members or public groups for this queue.
Click on "Save". The queue is created.

Salesforce Queue


Check this link to see the Salesforce editions that support Queues.