These are usually forms, used to formally evaluate and document an employee's performance, and to also get their acknowledgement that the review took place.

The review forms are also a great indication of how the organization's performance management process is; most employers review their staff every 6 or 12 months; doing a performance review is important, as it firstly highlights areas  in which an one needs to improve or develop and also points the individual to progress in their career. It helps both parties (the employee and the employer) to identify the areas in which the employee is doing well.