HTML
HTML, also known as HyperText Markup Language, is the code behind all of the text in websites, including the one that you're on right now. Once you start to get to know HTML, it starts to look a lot more organised.
CSS
CSS, which stands for Cascading Style Sheets, is the code for all of the colors and special effects on the internet. The background color, text font, and more are all determined by CSS.
JavaScript
JavaScript, commonly shortened to 'JS', is used to make most web pages interactive. Color-changing, file editors, and more are made in JavaScript.