Cross-platform development refers to the practice of developing software applications that can run on multiple platforms or operating systems. Some of the key features and contents of cross-platform development include:

Code Reusability: Cross-platform development allows developers to write code once and reuse it across multiple platforms, reducing development time and costs.

Reach: Cross-platform development allows developers to reach a wider audience by making their application available on multiple platforms.

Flexibility: Cross-platform development allows developers to choose the best tools and technologies for their project, regardless of the target platform.

Responsiveness: Cross-platform development allows for the development of responsive and adaptive apps, which can adapt to the different screen sizes and resolutions of various devices.

Hybrid App Development: Cross-platform development can be achieved by using hybrid app development frameworks such as React Native, PhoneGap, and Xamarin.

Progressive Web App: PWAs are web apps that are built and run on the browser but they can be installed on the device and run in offline mode. They can be accessed on multiple platforms and devices.

Cross-platform development can be done using various frameworks, languages, and tools such as:
React Native (JavaScript)
Xamarin (C#)
PhoneGap (HTML, CSS, JavaScript)
Flutter (Dart)
Ionic (HTML, CSS, JavaScript)
Testing and Debugging: Cross-platform development requires testing and debugging across multiple platforms, which can be a more complex and time-consuming process than developing for a single platform.
Limitations: Cross-platform development can have some limitations such as reduced performance, less access to native features, and limited control over the look and feel of the application.