A mail message consists of a header, which contains information about who the message was sent from, the recipient(s) and the route. Many of the header fields are not shown by default, but most programs used to read email will allow full headers to be displayed. This is then followed by the body of the message which contains whatever the sender wishes. lf the mail message is a formal one, it is customary although not obligatory to finish with your name, return address and other useful information as a signature. For example: