git branch is the command that manages branches within a Git repository.

The default branch is called master.

To create a new branch:

git branch <branch-name>

To see a list of all branches in the current repository:

git branch

Switching to another branch:

git checkout <branch-name>

Creating a new branch and switch to it in one step:

git checkout -b <branch-name>

Deleting a branch:

git branch -d <branch-name>

Create a branch with the changes from the current branch:

git stash
git stash branch <branch-name>

More information on git-branch manual page.