In what sense? You can use testflight[1] to bundle a version for specific users.
Naturally, you can't have it downloadable for the general public whilst it's under review but testflight is one of the more popular methods to share the app with clients/testers/team members etc.
This is specific to iOS. My app is on Mac store (desktop). I'm assuming from your answer that the app can't be available for public download when submitted to appstore for review.
Naturally, you can't have it downloadable for the general public whilst it's under review but testflight is one of the more popular methods to share the app with clients/testers/team members etc.
[1] https://testflightapp.com/