Git is an open source distributed version control system mainly used for source code management. It was designed and created by Linux Torvalds as an improvement on other version control systems like CVS and SVN. The document then discusses repository hosting on services like GitHub, GitLab, and Bitbucket, common Git workflows like the shared repository model and fork and pull, and different branching models including feature branches, Gitflow, and main/hotfix branches. Useful links are also provided on installing Git and different Git workflows.