HTML is a markup language which is used to create documents which contain the structure of a webpage consisting of a number of elements which define the page’s content.
The three main parts of an HTML element are the opening tag, the closing tag, and the content between them. To add extra information to an element such as a class name or a URL containing an image source, attributes are added to the opening tag of an element.
Some elements are considered semantic elements which means they have specific meaning such as the nav element which denotes a navigation section of a document, compared to a div which is a more general containing element.