It is necessary to add comment(s) in HTML

Answer 1

Optional, but you can just add comments to make the code more human-friendly as it will be easier to read to yourself and others , for example :
<!--code for the Top page below-->
Huge junk HTML code for the top page
<!--code for the Middle page below-->
Huge junk HTML code for the middle part of the page
<!--code for the bottom page below-->
Huge junk HTML code for the bottom part of the page

Answer 2

the comment help yourself when HTML code is huge.
<!-- comment here -->