message-required-headers

message-required-headers is a variable defined in `message.el'.
Its value is

((optional . References) From)

Documentation:
*Headers to be generated or prompted for when sending a message.
Also see `message-required-news-headers' and
`message-required-mail-headers'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.