Neena can use Comments while writing the code. It is a good programming practice. Comments improve readability. It is not the part of a program. Comments <! - and - >
Eg. <!-This is used to display an information->
<HTML>
<!-head section->
<HEAD>
<TITLE>Subscript</TITLE>
</HEAD>
<!-BODY section->
<Body>
<B> 'The symbol H <SUB>2</SUB>O represents water</B>
</Body>
</HTML>