Editor.md

Powerful open source Markdown editor.

Requirements

• Drupal Markdown - The Markdown module for Drupal, version 8.x-2.0 or higher.
• Editor.md - The Editor.md library distribution files.

Installation

• Install the Editor.md module as you would normally install any other
  contributed Drupal module.
• In the event your site is not using Composer, you must manually install
  Editor.md in /libraries/editor.md. Note: it is highly recommended that
  you install this module's dedicated fork instead of the upstream which is
  currently out of date.

Configuration

1. Navigate to Administration > Extend and enable the module and its
   dependencies.
2. Navigate to Administration > Configuration > Content Authoring > Text formats and editors.
3. Either create a new text format or choose an existing one to Configure.
4. On the format's configuration page, you can select Editor.md in the text
   editor dropdown and then continue to configure the editor as you desire.
5. Click Save Configuration when done.