35.1 The Format of the Mail Buffer

An email message must contain certain pieces of information, called headers, which specify the message's sender, recipient(s), and so on.

At the top of the mail buffer is a set of header fields, where you can enter this information. You can insert and edit header fields using ordinary editing commands. See Header Editing, for commands specific to editing header fields.

Some header fields are automatically pre-initialized in the buffer, when appropriate; other headers, such as ‘Date’ and ‘Message-Id’, are normally omitted from the mail buffer and created automatically when the message is sent.

The line in the buffer that says

     --text follows this line--

separates the header fields from the body (or text) of the message. Everything above this line is treated as part of the headers; everything below it is treated as the body. The delimiter line itself does not appear in the message actually sent. The text used for the delimiter line is controlled by the variable mail-header-separator.

Here is an example of what the headers and text in the mail buffer might look like.

     To: gnu@example.org
     CC: lungfish@example.com, byob@example.net
     Subject: The Emacs Manual
     --text follows this line--
     Please ignore this message.