Because of the nature of this question, I assume you are new to Web Design. Here are the basics.
HTML- Used to make the barebones of a website. All your titles, paragraphs, forms, images, and charts are made with HTML. You can make a website with only HTML, but it won't look especially pretty. Do learn this first though.
CSS- This is what makes a website look pretty. With a simple knowledge of CSS, you can transform your webpage from black and white documents into works of digital art. Learn this Next.
Hope this helps.