React Native is an open-source mobile application framework created by Facebook. It is used to develop applications for Android, iOS and UWP by enabling developers to use React along with native platform capabilities.
Ionic is a complete open-source SDK for hybrid mobile app development created by Max Lynch, Ben Sperry, and Adam Bradley of Drifty Co. in 2013. The original version was released in 2013 and built on top of AngularJS and Apache Cordova.
IOS is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that presently powers many of the company’s mobile devices, including the iPhone, iPad, and iPod Touch.