Git is a so-called distributed version control system. It helps developers work on the same source code, without creating problems like code conflicts caused by contradicting changes. Git makes it easy for everyone to see who modified some code, when, and why. It makes it easy to track what code is written for version 1.1 of the app, and what changed in version 1.2. It lets people see what lines of code some bug fixes changed, and so on. Long story short, Git allows multiple people to collaborate on the same source code.
You can learn more about Git by reading the DevOps: Git for Beginners blog. That way you get a quick intro. If you have time to learn more though, we recommend the KodeKloud Git for Beginners course. This explains the basic concepts of Git such as branching, merging, rebasing, reverting, etc. It includes visualizations and animations for a better understanding of the concepts. The learners also get access to the labs where they can get practical experience with Git.
Experiment with Git as much as you’d like by using this Git playground. The playground includes the git command preinstalled. You also get access to Gitea, something that will let you access a website similar to GitHub. It's basically a self-hosted web platform that lets you store source code in repositories, and perform various actions on it, through your web browser. But the git command can also interact with the Gitea service (for example, to upload new code from a local computer to a Gitea repository).
git add <file_names>
git commit -m “Message to describe the commit”
git branch <branch_name> (Creates branch)
git checkout <branch_name>
git merge <branch_name>
git clone <repository_url>