Android Support: If your package relies on native code or platform-specific implementations, you'll need to modify the Android configuration.

Check android Folder: Ensure your package doesn't have any platform-specific code in the android folder. This folder should generally be empty for a pure Dart package.

Dependencies: Ensure your package specifies any necessary platform-specific dependencies in the pubspec.yaml file. For Android-specific dependencies, use the flutter.plugin.platforms key.

Plugin Registration: If your package uses platform channels, ensure the method channel registration in Dart code is correctly handling the Android platform.

iOS Support: For iOS support, similar considerations apply as for Android:

ios Folder: Check the ios folder. If there's any Objective-C/Swift code or configuration required for iOS, ensure it's correctly set up.

Dependencies: Ensure your package specifies any iOS-specific dependencies in the pubspec.yaml file. Use the flutter.plugin.platforms key for iOS-specific dependencies.

Method Channel Registration: If your package uses platform channels, ensure the method channel registration in Dart code is correctly handling the iOS platform.

Web Support: Check for Web Support: Ensure your package doesn't use any native code that won't work on the web. For instance, any method channels or platform-specific code should be wrapped in platform-specific checks (if (kIsWeb) { ... }).

Dependencies: Declare any web-specific dependencies in the pubspec.yaml file using the web platform specifier.

Code Adaptations: Ensure your codebase follows web-compatible patterns. Certain packages or functionalities might not work the same way on the web due to browser constraints or differences.

Testing: Test your package thoroughly on Android, iOS, and web platforms after making modifications to ensure it works correctly on each platform. Use emulators/simulators and real devices for testing.

Documentation: Update your package's documentation (README.md) to inform users about the platforms your package supports and any platform-specific instructions they might need to follow.

Always refer to the official Flutter documentation, especially the guides related to platform-specific implementations and publishing packages for additional details and best practices.