HTML, or Hypertext Markup Language, is the foundation of the World Wide Web. It is a markup language that is used to create and structure content on web pages. HTML was first introduced in 1991, and since then it has evolved to become the standard language for creating web pages.

HTML works by using a series of tags, which are enclosed in angle brackets, to indicate how the content on a web page should be displayed. For example, the "<p>" tag is used to indicate a paragraph of text, while the "<img>" tag is used to insert an image.

HTML tags can also contain attributes, which provide additional information about how the content should be displayed. For example, the "<img>" tag can include attributes such as "src" to indicate the location of the image file and "alt" to provide alternative text for the image.

One of the key features of HTML is its ability to create hyperlinks, which allow users to navigate between different web pages. Hyperlinks are created using the "<a>" tag, which includes the destination URL in the "href" attribute.

HTML is not a programming language in the traditional sense, as it does not have the ability to perform complex calculations or operations. However, it can be used in conjunction with other web technologies, such as CSS (Cascading Style Sheets) and JavaScript, to create dynamic and interactive web pages.

In addition to its use in creating web pages, HTML is also used in email messages and other digital documents. HTML emails allow for more sophisticated formatting and styling than plain text emails, while HTML documents can include interactive features such as forms and embedded videos.

In conclusion, HTML is a fundamental part of the web and is essential for creating and structuring content on web pages. While it may seem simple on the surface, it is a powerful tool that can be used in conjunction with other web technologies to create dynamic and engaging user experiences.