HTML (HyperText Markup Language) is the code that is used to structure a web page and its content. For example, content could be structured within a set of paragraphs, a list of bulleted points, or using images and data tables. This article will give you a basic understanding of HTML and its functions.
Markdown is a lightweight markup language that you can use to add formatting elements to plaintext text documents. It is designed to be a really simple way to write in plain text and, with a few simple characters, tag it so that it will turn into really clean, really good HTML.
Many Markdown processors support custom IDs for headings and syntax highlighting for fenced code blocks. This feature allows you to add color highlighting for whatever language your code was written in.