If you want to write some quick markup text "on the road" with your Android device, this app is cool:
If you want to change markup to html on Android, load the markup with this editor. It has a markup view function which "shares" to your browser for viewing. If you share to the editor instead, you have converted your markup text to html.
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.