Elements <h1>, <h2>, <h3>, <h4>, <h5> and <h6> are used to create headings of various levels:
Headings are bold, and by default they are in some size, from largest <h1>to smallest <h6>.
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Heading in HTML5</title> </head> <body> <h1>First level heading</h1> <h2>Second level heading</h2> <h3>Third level heading</h3> <h4>Fourth level heading</h4> <h5>Fifth level heading</h5> <h6>Sixth level heading</h6> </body> </html>
When defining headings, keep in mind that there should be only one first-level heading on the page, that is <h1>. It acts as the main header of the web page.