When you are all through editing a message, you send it with the
command C-c C-c (mh-send-letter). You can give a prefix
argument (as in C-u C-c C-c) to monitor the first stage of the
delivery; this output can be found in a buffer called *MH-E Mail
Delivery* (see Miscellaneous Commands, Variables, and Buffers).
The hook mh-before-send-letter-hook is run at the beginning of
the command C-c C-c. For example, if you want to check your
spelling in your message before sending, add the function
ispell-message.
In case the MH send program44 is installed under a different name, use
mh-send-prog to tell MH-E the name.
The hook mh-annotate-msg-hook is run after annotating the
message and scan line (see Sending Mail).