Web development is the process of creating and maintaining websites using technologies like HTML, CSS, JavaScript, and databases. It enables online presence and functionality for businesses. There are two main types of websites - static sites with fixed pages for simple information, and dynamic sites that generate personalized content. Popular languages for web development include HTML, CSS, and JavaScript for front-end design and user interfaces, and languages like Python, PHP, and Ruby for back-end functionality and databases. Frameworks help streamline development by providing pre-built tools and structures. Security practices are also important to protect websites and user data.