How webpages work

What HTML does

HTML (HyperText Markup Language) gives structure and meaning to a page.
Browsers read HTML from top to bottom and turn tags into elements you can see and interact with.
Good HTML makes content readable even before any CSS is added.

The essential document shape

Every page should start the same way:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>My First Page</title>
  </head>
  <body>
    <!-- Content goes here -->
  </body>
</html>

<!DOCTYPE html> tells the browser to use modern HTML.
<html> wraps the whole page; add lang="en" for accessibility.
<head> holds the title and settings; <body> holds what people see.

Block vs inline elements (quick view)

Block elements (e.g. <h1>, <p>, <div>, <header>) start on a new line and stretch to fill the available width.
Inline elements (e.g. <a>, <strong>, <img>, <span>) sit inside a line of text without forcing a new line.
Use blocks to group sections; use inline elements for small pieces inside those sections.