There's two common objectives for performance reviews. Yours can include one or both
The objective is to assess the employee’s performance over a certain period of time to make key business decisions. Typically, these decisions include things like whether this person should get promoted, whether the employee deserves a raise, and the employee’s overall status within the company. These types of reviews are for the company to gather important information about the employee and typically happen 1-2 times per year.
The objective is to provide employees with feedback to highlight how they can improve. At the end of this review, employees know what they need to work on and what steps they need to take to be successful. These types of reviews are for the employee’s benefit, and ideally happen 2-4 times per year.