https://docs.docker.com/introduction/understanding-docker/#what-are-the-major-docker-components
Docker helps you ship code faster, test faster, deploy faster, and shorten the cycle between writing code and running code. Docker does this by combining a lightweight container virtualization platform with workflows and tooling
At its core, Docker provides a way to run almost any application securely isolated in a container.
Surrounding the container virtualization are tooling and a platform which can help you in several ways: