By now, you might be aware of NPSettings. Incase if its new to you, read this post.
Utility feature is enabled by default. Click on Utility Settings in NPSettings.
Under Rate My App section, enable the checkbox for IsEnabled entry if you want to use Rate My App feature.
In-case if you are using RateMyApp or OpenStore features, you need to setup your App store details. Go to Application Settings in Native Plugins.
Store Identifier for iOS is the numeric value you find when you open your App page on browser.
Store Identifier for Android is usually the bundle identifier.