HTTP Cookies are small pieces of data that websites store on your computer when you visit them. They help the website remember information about you, like your login details or items in your shopping cart. This makes your browsing experience smoother and more personalized. When you return to the same website, your browser sends these cookies back to the server, allowing it to recognize you. This way, you don’t have to re-enter your information every time. However, it's important to manage your cookies, as they can also track your online behavior across different sites, raising privacy concerns.