At the heart of most software development is some form of revision control, also known as version control or source control. While it's fairly straight forward for a single developer or even a small number of developers to share a source respository, it becomes more complicated when you grow to large numbers or wish to work with outside contributors. To effectively do this type of development, one really needs a centralized service.
Many students create free accounts on GitHub to host public and private repositories and manage software projects.
This webpage is not intended to be a git tutorial. If you need an introduction to git in general, we suggest you talk with a local developer or read the official git tutorial.