<h1> text </h1>causes the text to be displayed as a level 1 heading. This is boldest, largest heading form available. The text may be centred with one or two lines of clear space after the text. When printed this will appear at the start of a page.
Browsers
All browsers honour all aspects of the heading
also
<h2>,
<h3>,
<h4>,
<h5>,
<h6>
and general notes on
headings