Automatic emails can be defined as the emails which are sent out without human action. Automated emails help not only to avoid repeated tasks and also ensure the punctuality in email transfer. I can classify it in two types, predefined and dynamic based on nature of email body content.
predefined emails are delayed emails, which are created and set for future date. Basically, in this type email body needs to be created by us and set time for send. Check out below steps for creating delayed emails in MS Outlook. http://office.microsoft.com/en-us/outlook-help/delay-or-schedule-sending-email-messages-HP010355051.aspx
Similar like outlook, gmail too have such feature. Here is the addon https://code.google.com/p/gmail-delay-send/
On other hand dynamic emails are triggered through an email server using some scripts. It will be more beneficial for reports and logs. Here, the body of the email is created by script based on many factors. If you are interested in programming then check below resources.
For Google apps script