Don't know how copy file to userData during app's installation

How to copy (during app instal) a given file from project's root folder to the path, so that I can access it in my javascript like:

let path = electron.app.getPath('userData') + 'settings.json'

Is there an instruction we need to place in 'build' section of package.json of app's project ?
NOTE: I'm using electron-builder to build the executable for app I want to install in Windows.