How to open a .md file on Mac

A .md file holds text written in Markdown. Your Mac opens it without trouble, but it shows you the symbols instead of the formatting.

Why the file looks “broken”

Markdown is ordinary text with a few signs that describe the structure: # for a heading, ** around a word for bold, - for a list, vertical bars for a table. To show a real heading or a real table, you need software that understands these signs.

That is what you get when ChatGPT, Claude or another assistant hands you a brief “in Markdown”: the content is fine, but the layout does not appear while the file is open in a plain text editor.

# Customer portal launch

## Goal
Help each customer **find their invoices**.

| Step | Owner |
|---|---|
| Mockup | Lea |

Three ways to open a .md file

1. With TextEdit. Right-click the file, then “Open With” and “TextEdit”. The text is readable, but you see the Markdown symbols as they are. Fine for a quick look, not for reviewing a document.
2. With a code editor. Editors made for developers display .md files and, for some, a preview. They need to be installed, and their interface is built for code.
3. With Marko. The app shows the formatted document, lets you fix the text, then exports a PDF. The file stays an ordinary .md on your Mac.

Open a .md file in Marko

1. Download Marko and move it to the Applications folder.
2. Right-click your .md file, then “Open With” and “Marko”. You can also launch Marko and use the File menu, “Open File…”.
3. Fix whatever needs fixing. Saving is automatic.
4. To send the document to someone who does not have Marko, use “Export as PDF” in the File menu.

To make every .md file open directly in Marko: select a .md file in the Finder, press ⌘ I, open the “Open with” section, choose Marko, then click “Change All…”.

Save an AI answer as a .md file

If your assistant does not give you a file, copy its answer, create a new document in Marko and paste the text. Save it: you get a .md file you can reopen, fix and export.