I can send email in any format using
neomutt. I just use
Emacs (org-mode), instead of
vim. Although, I am a
vim user as well. But, I mostly use
Emacs with evil-mode.
.muttrc I have set up the editor to be
emacs instead of
vim. When writing a new email,
emacs up. Then I call "org-mode", write the message, and export to whatever format I want.
I can export to
PDF format. Then I save it and attach the
PDF file in my
/tmp. After that I can send to whomever.
If I want the
html format, I export that in the same way and I automatically can see the output, before sending the email.
Apart from that, there are many other export formats in org-mode. Just, choose what you want. For sending code to other people, just add the source code to whatever language you want. Everything is explained in the org-wiki.