what is the purpose of comments in html code example

Example 1: commenting in html

<!-- a comment in html -->

Example 2: html comment

<!--HTML Comment Example! HTML Comments do not affect your code in
any way, comments can be used to take notes to yourself, or if you 
are working with a team, this could be a good way to communicate 
without messing up any of your code. Comments will not be shown 
in your HTML webpage. -->