Answer 1

Git is a version control system or VCS for tracking changes in computer files, It is more specifically used to work on files or projects with multiple people. It's mainly used for software development purpose, however it can be also used to keep tracking changes in any files. It is compatible with dos / sql commands. It's fully free and open-source.
It'll be helpful for you if you're working in a team with different systems connected to a network or internet.