You can open a Markdown in Windows 10 and 11 OS using Notepad or any other text editor tool. However, such tools aren’t helpful to view the HTML output of a Markdown file. Therefore, we suggest you use those tools that let you view Markdown content as well as HTML content of that file. The best option for you would be using some best free Markdown Editor software available for Windows 11/10 that lets you open, view, and edit Markdown files.