A mobile application, also referred to as a mobile app or simply an app, is a computer program or software application designed to run on a mobile device such as a phone, tablet, or watch. wikipedia.org

Application software is a set of one or more programs designed to carry out operations for a specific application. Application software cannot run on itself but it is dependent on system software to execute. wikipedia.org

React is an open-source JavaScript library for creating user interfaces that aims to address challenges encountered in developing single-page applications. wikipedia.org

Android software development is the process by which new applications are created for the Android operating system. Applications are usually developed in the Java programming language using the Android Software Development Kit, but other development tools are available. wikipedia.org

Kotlin is a statically-typed programming language that runs on the Java Virtual Machine and also can be compiled to JavaScript source code. wikipedia.org

JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles. wikipedia.org

PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. wikipedia.org

MySQL is a relational database management system (RDBMS) that runs as a server providing multi-user access to a number of databases. wikipedia.org

Is a platform for web and mobile application. wikipedia.org

HyperText Markup Language (HTML) is the main markup language for web pages. HTML elements are the basic building-blocks of webpages. wikipedia.org

Cascading Style Sheets (CSS) is a style sheet language used to describe the presentation (that is, the look and formatting) of a document written in a markup language. wikipedia.org