An HTML file holds the basic structure of your website. It tells the browser what needs to be there for content. For example, what to show as the title for your website in the browser tab. In the case of this post, the browser tag should read “HTML Files: How to Create & Use”, as I’ve set this in the title tag of the HTML when I wrote this blog. In other words, it defines the structure and content of your page. If you compare your website to a house, the HTML is bricks and mortar, the walls and ceilings, and your house’s roof. It won’t tell you anything about the colour of the wallpaper – that’s what CSS is for.