What you can see in Employee Performance depends on your access:
Managers: objectives and performance reviews for their direct and indirect reports.
Administrators: objectives and performance reviews for all employees.
Give someone administrator access
To see all employees, a user needs to be set as an administrator in the Members tab for Employee Performance.
View another employee
To view objectives or performance reviews for any employee, even if they are not in your team:
Open Employee Performance.
Click Company view.
Select the employee.