Set User name & email
$ git config --global user.name "John Doe"
$ git config --global user.email johndoe@example.com

Set editor on Unix
$ git config --global core.editor emacs
Set editor on Windows

$ git config --global core.editor "'C:/Program Files/Notepad++/notepad++.exe' -multiInst -nosession"

Checking your setting
$ git config --list

https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup