HTML is a markup language used to define the structure and layout of web pages. HTML uses tags to mark elements like headings, paragraphs, links, images, and tables. To create an HTML page, the code is written in a plain text editor and saved with an .html or .htm file extension. The page can then be viewed locally in a web browser. Common HTML tags were also described such as <h1> for headings, <p> for paragraphs, <a> for links, <img> for images, and <table> for defining tables with rows and cells.