What is the purpose of <sub> tag

Answer 1

Example code:
https://code.sololearn.com/WqganlVhIS9K/?ref=app

Answer 2

It is used for text formatting.
Example:-
Superscript:
X²

Subscript:
H₂O
It is used for subscripting a text.

Answer 3

when you want to write equations, this tags come handy

Answer 4

when you want to write math equations

Answer 5

thank you for ur explinations.now IAM clear...