If you have your CSS code in an external CSS file say "style.css", use this method,
HTML:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="styles.css">
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>
If you want to include CSS inside your HTML document, use the <style> tag as in this method,
HTML:
<!DOCTYPE html>
<html>
<head>
<style>
body {background-color: blue;}
h1 {color: black;}
p {color: red;}
</style>
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>
Or you can use Inline CSS like this (not recommended),
HTML:
<h1 style="color:blue;">This is a Blue Heading</h1>
