The most commonly used tool for version control of software projects is Git. It allows developers to track changes in source code over time, collaborate on projects, and manage code revisions efficiently. Git enables teams to work simultaneously on different features or fixes without creating conflicts. Developers can create branches to experiment and merge changes back into the main codebase safely. Platforms like GitHub build on Git by providing additional features such as issue tracking, project management, and social coding, further enhancing collaboration within software development teams.