When reading/getting, the values are read from the system, global and repository local configuration files by default, and options --system, --global, --local and --file <filename&GT; can be used to tell the COMMAND to read from only that specific location. When writing, the new value is written to the repository local configuration file by default(--local), and options --system, --global, --file <filename> can be used to tell the command to write to that location.

• Set a user's email-id (to be recorded in any newly created commits) : git commit --global user.email "sc.2017.india@gmail.com" 
• Set a user's FULL name (to be recorded in any newly created commits) : git commit --global user.name "Sandeep Choudhary"
• Set signed key for a signed TAG or commit : git config --global user.signingkey <your-signed-key-here> Command 'git config --global --list' will show all of the current global settings/options.
• Configuration saved using '--global' is STORED in a file '.gitconfig' in the current user's home directory. User's name and email-id should be set before using git further.