A bigger element can contain smaller elements inside of it. For example, in this page see the CODE elements in the first paragraph, and the I elements in the secod paragraph.
The overall structure of the web page
The web page begins with a doctype line. The rest of the web page is one big element called the HTML element. The HTML elements contains two smaller elements, the HEAD element and the BODY element. The BODY element should begin with an H1 element, specifying the heading for the page. The HEAD element should begin with a TITLE element, specifying the text in the page's tab in the web browser.
Some elements are just a single tag
A very small element that contains no text
is written with only one tag,
ending with a diagonal slash.
For example, the BR element causes a line break,
and the HR element draws a horizontal line.