Cross-platform frameworks are tools that allow developers to create applications that can run on multiple operating systems, such as iOS, Android, and Windows, using a single codebase. This means that instead of writing separate code for each platform, developers can write it once and deploy it everywhere, saving time and effort. Popular examples include React Native and Flutter. These frameworks simplify the development process by providing pre-built components and libraries, making it easier to design user interfaces and manage app functionality. As a result, businesses can reach a wider audience and reduce costs, while users enjoy a consistent experience across different devices.