Git clone - Cloning a repository creates a linked copy of the repo. The copy can be synced with the master repo to get updates made by other developers working on the repo using 'git push' and 'git pull'.
Git branch - Creating a branch from a repo allows you to develop changes without affecting the main repo. Branches are used to develop features or changes that may be merged back into the target repo.
Git fork - Forking a repository creates a new copy of that repo that is independent from the target repo. Developers working on the main repo don't see the forked repo. Forking is used when you want to isolate the work you do on a project separately from the main repo, like if you're developing major changes or features.