When installing Studio, you can choose to enable only GIT, SVN or TFS functionality.
After installation, the options are available and editable in Backstage > Team:
The Add to Source Control button in the status bar offers shortcuts to GIT Init, Copy to GIT, Add to TFS, and Add to SVN.
The GIT Version Control offers an overview and instructions on how to work with GIT-versioned projects in Studio.
Part of working with versioned files is the possibility to compare changes between the local version of the file and the one checked in the repository. You can do so using Workflow Diff.
If you want to compare two similar files in the same automation project, use Compare Files, which is also available for unversioned files.