An auto-responder email is a a message that's sent from your email address as the reply to each email that you receive. The content is predefined and it is sent automatically, so each and every person who contacts you via electronic mail will get it once their message is received on the server that takes care of your email messages. This feature is used if you need to inform people about different things, such as being out of the office for a given period of time or that the purchase has been received and is currently being prepared. The auto-responder email furthermore serves as a verification for the people who make contact with you that their email has been received, even if you are not able to read it and get back to them straight away. It could contain virtually any text of your choice and it can be modified with respect to the exact occasion.