To allow guardians to be send messages to the administration at the school, the message box for school administration must be activated (1). If students should also be able to send messages to the school administration, the message box for student must be activated (2). If this is not visible in your school, it can be turned on under "SETTINGS" (3)
When guardians send messages, they can then choose the school administration mailbox as the recipient of a message. In the picture below, mailbox for communicating between school administration and parent has been renamed to 'Parent - Staging school' so any message sent to this box, all the person with access level as school administration member will receive the message.
There are users who have been given access to "School Administration" who receives messages sent from parents to "School Administration"
School Administration staff that should not receive message sent from guardians, should be give the role "School Employee".