Hi Reham
There is a whole forum dedicated to this topic, visit https://moodle.org/mod/forum/view.php?id=596. You starting point is its documentation https://docs.moodle.org/en/Performance and https://docs.moodle.org/en/Performance_FAQ, It is also worth reading similar discussions in that forum.
There is a whole forum dedicated to this topic, visit https://moodle.org/mod/forum/view.php?id=596. You starting point is its documentation https://docs.moodle.org/en/Performance and https://docs.moodle.org/en/Performance_FAQ, It is also worth reading similar discussions in that forum.