6 files:
%ALLUSERSPROFILE%\Git\Config (Windows only)- (system)
/etc/gitconfig, with being the git installation path. (on Windows, it is \mingw64\etc\gitconfig) - (system)
$XDG_CONFIG_HOME/git/config (Linux/Mac only) - (global)
~/.gitconfig (Windows: %USERPROFILE%\.gitconfig) - (local)
.git/config (within a git repo $GIT_DIR) - a dedicated file (with git config -f), used for instance to modify the config of submodules:
git config -f .gitmodules ...
the command line with git -c: git -c core.autocrlf=false fetch would override any other core.autocrlf to false, just for that fetch command. The order is important: any config set in one source can be overridden by a source listed below it.