An auto-responder email is a a message which is sent from your mailbox as the answer to each email that you get. The message is predefined and it is sent automatically, so each and every individual that contacts you via e-mail will get it the instant their message is received on the server that handles your e-mails. This feature is used when you need to inform people about various things, for example being out of the office for a given time period or that the purchase has been received and is currently being prepared. The auto-responder email in addition operates as a verification for those who contact you that their e-mail is received, even if you are unable to read it and make contact with them straight away. It could contain any text of your choice and it may be edited based on the specific occasion.