Git is an open-source version control system that allows developers to track changes to code over time, work on projects simultaneously without overwriting each other, and revert to previous versions if needed. GitHub provides a user-friendly interface for hosting Git repositories and collaborating on projects, with features like bug tracking and project management. The presentation introduces Git and GitHub, explaining how they address issues with earlier centralized and distributed version control systems by allowing decentralized, fast collaboration through local cloning of repositories.