HTML is the most basic programing langue involved in Web Development. Honestly, HTML is about as close to just literally writing text on a page as programming gets. An HTML document is often first thing that a Web Developer would create, because the first thing that a webpage needs is structure - even before content is added the structure of the page needs to be decided. Most of the styling of web elements has been handled by CSS for most of recent internet history, but the management of what is on a page and what order it's shown in is still decided by HTML.