Ionic is a framework that helps you to create hybrid applications, thus you will have only one codebase for both IOS and Android. The latest version of ionic is ionic 4. Since ionic is written using web languages, then it uses cordova to be able to use native device functionalities.
Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency. Git can be used to track old versions of files and to check all the different changes.