Developing apps targeting multiple device platforms with Apache Cordova in Visual Studio

With Cordova in Visual Studio, one can develop an app targeting Windows 10 (unitfied Windows OS for PCs and mobile devices), Android and iOS.

The most important thing for one to keep in mind when developing such type of apps is they are hosted apps.  In other words, they are essentially web pages running on a web engine. 

This beginner's guide is a good start point.

Uno Platform is the best one for targeting multiple platforms.