Markdown export is disabled by default in org version 9.1.9. As far as I can see the manual does not indicate any way to enable this. Perhaps it would be prudent to include this info in the Markdown Export page [0] of the manual. The way it is currently written it appears as if this should work out of the box.
The only time the relevant inclusion is mentioned (require 'ox-md) is mentioned int he manual is in the Exporting Chapter [1], but here it is not explained what this does. [0] https://orgmode.org/manual/Markdown-export.html [1] https://orgmode.org/org.html#Exporting -- Matthew Brecher m...@yhete.com