In the Identity section, update the Build identifier to a unique
build number used to track this build on App Store Connect.
Each upload requires a unique build number.

Finally, create a build archive and upload it to App Store Connect:

Create a release Archive of your application. From the base directory of
your application project, run the following.
    
flutter build macos

Open Xcode and select Product > Archive to open the archive created
in the previous step.

Click the Validate App button. If any issues are reported,
address them and produce another build. You can reuse the same
build ID until you upload an archive.

After the archive has been successfully validated, click
Distribute App. You can follow the status of your build in the
Activities tab of your app’s details page on
App Store Connect.