H header's are used to structure the content of your document. For instance you might want to indicate a header or divide your page up with sub headings. This lets search engines know about the content structure of your document. For instance the H1 heading defines the most important heading while the H6 heading defines the least important heading. In most cases, you won’t need to use the H1 header within your article as the H1 header will be added when creating your article’s 'Title' in Joomla!. Search engines place a high value on the text inside H tags, so make sure that your H headings are well-represented within your article.
For instance you might write something like this in HTML:
<h2>Sub Header<h2>
When outputted on your page it will look like this:
Sub Header
Here are a few other examples of h headers:
Heading 1 sample
Heading 2 sample
Heading 3 sample
Heading 4 sample
Heading 5 sample
Heading 6 sample
Creating header's
Content editors simplify this process and will do most of the work for you. To do this, start by selecting your header text and then select: 'Heading 1' from the Format list as seen below: