Git is a free and open source version control system. What this basically means is that you can use Git to store your projects and their files and it will keep track of different versions and changes to the files for you. You can use Git to store and manage files locally on your PC but most likely you will want to use one of the free cloud services that allows you to store the files online. Storing the files online makes it easier to share your projects and it also serves as a way to back up your file in case your PC crashes.