If you're just trying to find out where npm is installing your global module (the title of this thread), look at the output when running npm install -g sample_module
$ npm install -g sample_module C:\Users\user\AppData\Roaming\npm\sample_module -> C:\Users\user\AppData\Roaming\npm\node_modules\sample_module\bin\sample_module.js + [email protected] updated 1 package in 2.821s