Web applications are built using web technologies such as HTML, CSS, and JavaScript, and they can be created for a variety of purposes, including e-commerce, social networking, project management, and more.

Some of the benefits of web applications include:

• Accessibility: Web applications can be accessed from any device with an internet connection, making them highly accessible.
• Scalability: Web applications can handle large numbers of users and can be scaled easily to accommodate increased traffic.
• Cross-platform compatibility: Web applications can be accessed from different operating systems and devices, making them highly compatible.
• Easy maintenance: Since web applications are centrally hosted, they can be maintained and updated more easily than traditional desktop applications.

However, there are also some challenges associated with web applications, such as security risks, compatibility issues, and performance concerns. To address these challenges, web developers need to follow best practices for web application development and regularly update and maintain their applications.