Markdown
Edit .md files visually or as source. The file stays plain Markdown. There is no PDF: the visual editor is the preview.

- Visual / Source. Switch editors at any time.
- Toolbar. Adds strikethrough and task lists. Underline, color, superscript and subscript are not in Markdown.
- Contents. The headings of the file. Click one to go there.
Start a file with File › New › Markdown File.
Not in Markdown
No citations, cross-references, or equation, figure and table numbers. Comments and suggestions work.