First, you need to add a SMTP Server( 6 steps).
1 Click "Add SMTP Config" button which can be found at Domain->Setting->General Setting.
2 Enter your full email address (firstname.lastname@example.org) in the Sender Email field.
3 Enter your name in the Sender's name field.
4 Enter your SMTP Server address in the SMTP Server field.
5 Enter your email username in the SMTP Username field. Enter your password in the SMTP Password field.
6 Check the Use SSL box if your email server requires secure connection.
This picture shows how to config with gmail.
Second, use Event Manager to send a email to a specified receiver,You can also specify subject,priority,text and attach file.