There are a view different ways to enter the composer; i.e., from other
mu4e views or even completely outside.
If you want the composer to start in a new frame or window, you can configure
the variable mu4e-compose-switch; see its docstring for details.
You can start composing a completely new message with mu4e-compose-new
(with N from within mu4e.
To compose a reply to an existing message, you can use mu4e-compose-reply
(with R) from within the headers view or when looking at some specific
message.
If you want to reply to all recipients of a message, there is
mu4e-compose-wide-reply, by default bound to W. This is often
called “reply-to-all”, but mu4e follows the Gnus terminology “wide
reply”.
By default, the reply will cite the message being replied to. If you do not want
that, you can set (or let-bind) message-cite-function to
mu4e-message-cite-nothing.
See (message)Reply and (message)Wide Reply for further details.
Note: in older versions, mu4e-compose-reply would ask whether you
want to reply-to-all or not (there was no separate “wide” reply); if you are
nostalgic for that old behavior, you could add something like the following to
your configuration:
(defun compose-reply-wide-or-not-please-ask () "Ask whether to reply-to-all or not." (interactive) (mu4e-compose-reply (yes-or-no-p "Reply to all?"))) (define-key mu4e-compose-minor-mode-map (kbd "R") #'compose-reply-wide-or-not-please-ask)
You can forward some existing message with mu4e-compose-forward
(bound to F) from within the headers view or when looking at some specific
message. For further details, see (message)Forwarding.
To influence the way a message is forwarded, you can use the variables
message-forward-as-mime and message-forward-show-mml.
Occasionally, it can be useful to “supersede” a message you sent; for this,
there is mu4e-compose-supersede.
This drops you into a new message that is just like the old message (and a
Supersedes: message header). You can then edit this message and send it.
Superseding is only possible for messages you sent, as determined by
mu4e-personal-or-alternative-address-p.
This wraps message-supersede.
You can re-send some existing message with mu4e-compose-resend from within
the headers view or when looking at some specific message.
This re-sends the message without letting you edit it, as per (message)Resending.