If you're using React Native for app development, you can send a .apk and .aab file to the client.

To generate an apk file, follow the given steps:

Move to the Android folder as cd android

Then run the following command to make the apk file: ./gradlew assembleRelease

After the execution of the above command, the APK file can be located at: your_project\android\app\build\outputs\apk\release

Then run the following command to make the abb file: ./gradlew ./gradlew bundleRelease