What Git is
Git is a distributed version control system used to record changes to files and coordinate work between developers. Instead of keeping only the latest copy of a project, Git stores a history of snapshots so you can inspect, compare, restore and combine versions of your work.
Git is distributed, which means a normal clone contains the repository history locally. You can create commits, inspect history and create branches without being connected to a remote server.
Why version control matters
Without version control, developers often create folders such as project-final, project-final-2 and project-final-real. Git replaces this fragile process with named commits and branches. Every commit records a specific state of the project and can contain a meaningful message describing the change.
Git and GitHub are different
Git is the version control tool. GitHub, GitLab and Bitbucket are hosting and collaboration platforms that can store Git repositories remotely. You can use Git without GitHub, and you can work with a GitHub repository through the Git command line.