Markdown is a plain text markup language, originally designed by John Gruber, which is used to create convert easy-to-read text to formatted HTML. If you are just getting started with Markdown, you might want to visit one of these great resources to learn about what Markdown is and what it can do for you:
Drafts & Markdown
Drafts supports Markdown in several ways. First, by default, Drafts does basic syntax highlighting of some of the most common Markdown formatting tags. This means that as you type, headers, lists, emphasis, links and some other common markup will be highlighted in the text. This feature can be disabled in appearance settings.
Drafts can also convert your text to HTML, and output that HTML. The HTML can be previewed using one of the built-in preview actions, or through customized HTML/CSS HTML Preview actions steps. The output can also be used to send rich-text HTML emails (using the "Markdown > Email" action), copied to the clipboard, saved to files, saved as rich text to Evernote or Google Docs, or many other options.
The original version of Markdown, as written by John Gruber, has been extended by others and there are now a number of different popular variations of Markdown which support additional markup for citations, tables and the like which where not in Gruber's original syntax.
Because of these variants, Drafts offers three different built-in Markdown processors. Each has its own advantages, quirks.
Which Markdown processor to use can be configured in Drafts Settings. If you find the output is not what you were expecting, it might be a good idea to try one of the other processors. The three available are:
MultiMarkdown (MMD) - Default
MultiMarkdown is a "a superset of the Markdown syntax, originally created by John Gruber. It adds multiple syntax features (tables, footnotes, and citations, to name a few)". Created by Fletcher Penney, MultiMarkdown is one on of the most commonly used Markdown processors. For details on MultiMarkdown, read the MultiMarkdown Syntax Reference.
The Discount processor most closely adheres to the original Markdown syntax. If your use of Markdown is only very simple, and you do not need the advanced formatting features, Discount may be for you. Assume the output of this processor will support closely match that of Gruber's original Perl version and the original Markdown Syntax guide.
Github Flavored Markdown
Github, the popular source code repository service, developed its own set of extensions to Markdown. The Github Flavored Markdown processor adds tables, fenced code blocks, and some other new syntax while still being more flexible than MultiMarkdown. To learn about this processor, see: Github Flavored Markdown User Guide