Docker is a popular platform for creating, deploying, and managing applications in containers. Containers provide a lightweight and portable way to package applications with their dependencies, making it easier to move them between environments and ensuring consistency across different platforms. Docker simplifies the process of building, shipping, and running applications, making it easier to develop, test, and deploy software in a fast and efficient way. It is widely used by developers, IT professionals, and organizations of all sizes to improve the efficiency, scalability, and portability of their applications.