Every application from source is required to be built into an apk or appbundle for upload to Play Store. If you want to make it into apk, you can type the command in terminal. Don’t forget to change the directory into root folder. The command for build apk is “flutter build apk”. After you type it, press “Enter” and wait the process till done. The APK will be in the folder root folder/build/app/outputs/flutter-apk/app-release.apk or you can see the result in terminal after the process done.
After you build the relase aplication, you can share the APK file. But if you want to upload to Play Store, you need to build the source code be appbundle or .aab extension file. This is the command for build appbundle “flutter build appbundle”. That is same like build apk file, you must wait the process untill done to see result place. Usually located in root folder/build/app/outputs/bundle/release/app-release.aab.