How to write code

How to write code HTML-CSS.

What does <p> means

Hi there and welcome to the forum!

Please take a look at this perfect place to start:
https://www.freecodecamp.org/learn/responsive-web-design-v9/

As it says,

This course teaches the fundamentals of HTML and CSS, including modern layout, design, accessibility, and responsive web development.

And I’ve edited your post to improve the readability of the code. When you enter a code block into a forum post, please precede it with three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add the backticks.

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (').