Git is a version control system created by Linus Torvalds that allows developers to track changes to code. GitHub is a free online repository that hosts Git repositories and allows developers to share code and collaborate on projects remotely. GitHub also allows developers to showcase their work and share their code publicly, potentially helping with job applications by including a GitHub URL. Git uses snapshots of files, adding, committing, and pushing changes to track a project's evolution over time through simple commands like init, add, commit, push, clone, and branch.