This paper describes the whole process of creating a simple mobile application with new, easier and more practical JavaScript language. JavaScript is an object-oriented scripting programming language which is based on Java programming language, but unlike Java, it is not class oriented programming. React Native JavaScript framework is maintained and further developed by the group of individuals and company's with Facebook in front. In February 2015. React Native is introduced to the public and in March of the same year it became ''Open source''.That way it was enabled to all that are interested in ReactNative to modify, inspect, change and share the code which helps in further development and the adjustment of React. Till the 18. April 2017. React Native was the newest version of React, then React Fiber was announced which would become the foundation of every user interface upgrades. Goal of the React Native is to standardize a simplified version of JavaScript and to make the writing code and creating applications easier to programmers. Some of the applications that were built using React Native are: Facebook, Instagram, Skype, Wix… In this paper theoretical background is explained as well as downloading and installing needed software and their use for creating a mobile application. Besides downloading and installing, the example of how to create mobile application for creating notes is shown. The code is described and every visual change is shown through the pictures.