HTML Comments are that part of code which is not visible to viewer.
Any number of lines can be commeted by HTLM comments.
<!--Content-->
or
<!--
Content
Content
Content
-->
HTML Comments can be used in two ways.
Single Line comment used for single line or element, mostly it is used as hints for developers to understand code in future.
Single line comment is used for only one line and you can put comments any where inside a code like you can put comments left side, inline or right side of a code.
Multiline comments are used to comment group of lines or blocks of code.
<!--
<p>this will not be displayed in browser</p>
<p>this will not be displayed in browser</p>
<p>this will not be displayed in browser</p>
-->
this will be displayed in browser
You can see the output of example one and two, the commented section of code did not displyed in browser so you can use comments for your hints or guide lines in your code.
Single line comment and multiline comments have same syntax. Multiline comments are used for more than one line and you can put comments any where in your code like you can put comments top or bottom of your code.
Open notepad or any other text editor, follow the following points.
save file with name task.html or task.htm and then open it using any browser and see results.