Empty elements, which only have an opening tag.
An example is the paragraph <P> tag:
<P>This is a paragraph. This is a paragraph. This
is a paragraph. This is a paragraph. This is a paragraph. This is a paragraph.
This is a paragraph.
Container elements, which have both an opening
and closing tag that surround the content. Closing (or end) tags
are the same as the open tag except they are preceded with a slash (/).
An example is the Header 1 <H1> tag:
<H1>This is a Heading Level 1</H1>
NOTE: There are literally billions of HTML pages on the Web (go ahead, count them!)
There are only 91 HTML elements (tags) to encode those pages. Hard to believe? See the W3 List of HTML Elements for yourself.