what is an md file code example

Example 1: what is a markdown .md file

A file with the .MD or .MARKDOWN file extension might be a Markdown Documentation file. It's a plain text file that uses the Markdown language to describe how to convert a text document to HTML. README.md is a common MD file that holds text instructions.

Example 2: .md file?

An MD file is a text file created using one of several possible
dialects of the Markdown language. It is saved in plain text format 
but includes inline symbols that define how to format the text
(e.g. bold, indentations, headers, table formatting)