Mobile App Development

The best resources for learning these app development courses are youtube, free courses udemy etc.

Google Developers Training

React Docs

Xamarin

Angular

Pluralsight 60 days free android courses.

App Development

Different Platforms

Android Apps

Android is a mobile operating system developed by Google which has 87% of market share in the world.

Xamarin

Xamarin is a Microsoft-owned San Francisco, founded in May 2011 by the engineers that created Mono, Mono for Android and MonoTouch, which are cross-platform implementations .With Certfication.

React Native

Build native mobile apps for android and ios using JavaScript and React.You can directly start with react-native instead of react.

Ionic Framework

Ionic is the app platform for web developers. Build amazing mobile, web, and desktop apps all with one shared code base and open web standards.

Flutter by Google

Flutter is an open-source mobile application development SDK created by Google. It is used to develop applications for Android and iOS, as well as being the primary method of creating applications for Google Fuchsia.

Apache Cordava

Apache Cordova is an open-source mobile development framework. It allows you to use standard web technologies such as HTML5, CSS3, and JavaScript for app development.

Apart from these you can also check some more..

Phonegap