Mac OS X Softwares to Outline mode

Typora is a minimalist Markdown editor that unifies writing and previewing into a seamless experience. It provides a distraction-free environment with real-time rendering, allowing users to focus solely on their content without the need for separate preview panes or modes. It supports a wide range of Markdown features and offers flexible export options.

Org-mode is a powerful and flexible mode for GNU Emacs, designed for note-taking, project planning, to-do list management, and authoring documents. It utilizes simple plain text files with intuitive markup.