.Net is a free, cross-platform, open source developer platform for building many different types of applications. With .NET, you can use multiple languages, editors, and libraries to build for web, mobile, desktop, games, IoT, and more. NET is important because it is a widely used and popular software development platform. It is being used by businesses of all sizes and industries to build sophisticated applications. Today.NET is a powerful tool that can be used to build web applications, Windows-based applications, and console applications.