Push notifications are crucial for mobile applications, providing a dynamic alternative to emails by enabling real-time communication and enhancing user engagement through timely alerts and updates. This guide details the process of integrating push notifications into React Native applications for both iOS and Android platforms using OneSignal. It involves setting up a new React Native project, configuring credentials such as iOS push certificates and Firebase Server API keys, and installing the OneSignal SDK. The tutorial also covers the setup of notification capabilities in Xcode, including the creation of app identifiers and provisioning profiles, and the configuration of app groups for analytics purposes. For Android, it explains the use of Firebase project settings to obtain necessary keys for OneSignal integration. The final steps involve initializing the OneSignal SDK in JavaScript and testing push notifications to ensure functionality, with all metrics viewable on the OneSignal dashboard. This comprehensive approach allows developers to effectively implement push notifications, enhancing the interactivity of their mobile applications.