how to choose the user in git code example

Example 1: add email to git config

To set your global username/email configuration:
Open the command line.
Set your username:
git config --global user.name "FIRST_NAME LAST_NAME"
Set your email address:
git config --global user.email "[email protected]"
To set repository-specific username/email configuration:
From the command line, change into the repository directory.
Set your username:
git config user.name "FIRST_NAME LAST_NAME"
Set your email address:
git config user.email "[email protected]"
Verify your configuration by displaying your configuration file:
cat .git/config

Example 2: git user config

$ git config --local user.name "John Doe"
$ git config --local user.email [email protected]