HTML

HTML is great. It defines the structure of webpages and it determines how data is displayed online.
What you're looking at right now is HTML code, read and interpreted by your browser. But this doesn't make HTML a programming language.

A Markup Language

HTML is a type of markup language. It encapsulates, or "marks up" data within HTML tags. The
HTML describes the data to the browser, and the browser then displays the data accordingly.

For example:
If we want to write the chemical equation H₂ + O₂ = H₂O

or Mathematical equation X² + Y² = Z²

or Special characters & ©

you should use the suitable tag for each one :)