Setting the ‘From’ field to send messages from the shared mailbox
1. Compose a new email. If the From field is not already visible (above the To:.. field) select Options > From within the new email window.
2. Select the From field > Other Email Address… When prompted enter the Display Name or email address of the shared mailbox and select OK. When the From field is selected this should now display the email address of the shared mailbox as an available option.
The new message window can now be closed. If prompted to save the message as a draft select No, as the ‘From’ setting has already been applied.