To send Email, go to Messaging > Send Email. Here you can see two tabs present at top right corner in the send Email page for sending email to a Group or Individual.
Send Email to Group-
To send Email to Group (Patient, Doctor, Admin etc), click on the Group tab present at top right corner of the page then enter the details that is message Title, Attachment, Message and select Message To (Patient, Doctor, Admin etc) and then click on Send button.
Send Email to Individual-
To send Email individual, click on the Individual tab present at top right corner of the page then enter the details message Title, Attachment, Message, Select user type from drop down and then search for the user name in the textbox then select searched user or users and click on Send button.