If you want to test this on a fresh new repository, then you can do the following prep work:

• Quickly create a new folder and cd into it:

mkdir my-repo ; cd my-repo

• Then initialize a new git repository:

git init .

• After that create a new branch:

git checkout -b wrong-branch-name

• Then check your the available branches with the following command:

git branch

Output:

  main
* wrong-branch-name

• Then similar in order to rename the branch you could just run the following command:

git branch -m wrong-branch-name correct-branch-name

• If you want to rename your current branch, you could just run the following:

git branch -m my-branch-name

After that, if you run git branch again you will be able to see the correct branch name!

An easy way to remember the -m flag is from the mv command in Linux, the mv command is used to move files but also rename them, just like the -m flag for Git!

This is pretty much it!
Hope that this helps.
Regards,
Bobby