One of the core principles of Scrum is working software over software documentation. But it doesn’t mean there will not be any documentation but yes, they need to keep at its minimum. It is more important to think about users’ goals than to list the attributes of a solution.

• In Scrum, we consider the requirements as User Stories. They are similar to the use case scenario. But use cases till tend to be larger than single story and can be more prone to containing embedded assumptions about user interface.
• Use cases are much more complete than user stories. Use cases are designed to be permanent artifacts of the development PROCESS while user stories are more transient and not intended to outlive the iteration in which they are developed.
• In the requirement documents use cases are written so that developers and customers can discuss them and agree to them. User stories are written to facilitate RELEASE planning and to serve as reminders to fill in requirements details with conversations.
• User stories emphasize verbal communication. Written LANGUAGE is often very imprecise, and there’s no guarantee that a customer and developer will interpret a statement in the same way.
• Traditional documents are very tiring, tedious, error prone and time consuming compared to user stories.
• In this case, time was wasted WRITING the three-fourths of the document that the team won't have time to develop, and more time will be wasted as the developers, analysts, and customer iterate over which FUNCTIONALITY can be developed in time. With stories, an estimate is associated with each story immediately. The customer knows the velocity of the team and the cost of each story.