How to make a Space of Comments?

Answer 1

To have "a space of comments" in a html page, guessing you mean a comment zone for a blog-like site, you need to handle database to store and retrieve them, and to serve dynamically your pages with a back-end web framework ^^

Answer 2

comments in html are written as <!-- text --> or <!--
multi
line
text
-->

hope it helps,
Kurios