GitHub: more than Version Control
GitHub is not only used as a version control system, but also contains project management as well documentation and integration with other tools.
Documentation with Markdown
Markdown is a basic markup language, which is typically translated to HTML. It is extensively used in GitHub projects to provide documentation. For instance, if a README.MD file is provided, the HTML output will be featured on the GitHub repository web page.
Markdown Cheatsheet provides an overview/
Deploy websites with GitHub Pages or Netlify
A GitHub repository can be used to host a website, for instance containing project documentation or a course on GitHub. The site contents are typically provided in markdown and together with other assets, such as Cascading Style Sheets (CSS), images, etc. stored in a repository. After a git push, a deploy script is triggered which generates the HTML and deploys it in on a webserver. GitHub Pages offers a static site generator, based on Jekyll. Netlify provides more configuration possiblities.
For example this site is hosted on GitHub, deployed and hosted with Netlify. Upon pushing to the repository on GitHub, Netlify is triggered to start a VuePress build. Half a minute later, the changes are already deployed on the website.
More on Git & GitHub