If you are planning to build an app for mobile,then you might wonder in which platform you should develop an app? An Android app or An iphone app. Mostly, I can suggest the app platform based on your user market. If your app's user is mix of both than you need to develop an app for the both the platform. As a cost concern developing an app for two platform is a costly solution for your business. 
You can use the cross platform for developing your app. Here, You can understand everything about the Cross Platform Mobile App Development.
In this cross-platform mobile app development article, will surely save you a lot of time during development life-cycle and help you reach the largest number of users by developing and deploying your app on different platforms.