greytHR provides you multiple reports to get details of monthly attendance. Navigate to Reports > Reports Gallery and search for Attendance Summary Report and Attendance Consolidated Report. These reports provide details of monthly attendance of employees.
Apart from reports, you can also view the monthly attendance data per employee along with their Sick Leave and other holiday information, under Attendance Muster. To navigate to the Attendance Muster page, click Leave > Information > Attendance Muster.