Wireframes and mockups can help, but there’s no question that most end users have some difficulty putting these elements together with written requirements to arrive at a good picture of what they will be getting.
As work is completed, it can be reviewed and evaluated by the project team and customer, through daily builds and end-of-sprint demos. Agile relies on a very high level of customer involvement throughout the project, but especially during these reviews.
Scrum is an agile process that allows us to focus on delivering the business value in the shortest time. It rapidly and repeatedly inspects actual working software. It emphasizes accountability, teamwork, and iterative progress toward a well-defined goal.
The Scrum Framework usually deals with the fact that the requirements are likely to change or most of the time not known at the start of the project.