You can create a watch-only app—that is, a watchOS app that has no iOS companion app—and offer it for purchase directly from the App Store on Apple Watch. Watch-only apps are also available to customers on the iOS App Store.
Select the Watch App template under the watchOS platform when you create your Xcode project. On the first sheet that appears, you’ll have the option whether to include a notification scene or complication.
The project will have a [Project Name] target that contains project settings but no files. The embedded WatchKit app and WatchKit extension targets must have the same bundle ID prefix as the [Project Name] target.
In the toolbar, choose an Apple Watch simulator or real device from the scheme menu. For watch-only apps, iOS Simulators and devices don’t appear in this menu. Then click the Run button. If you choose a simulator, the Apple Watch Simulator launches without an iOS Simulator.
You can distribute a beta build using TestFlight or distribute it to registered devices. After you create the archive, select the archive in the Archives organizer and in the inspector, view details about the archive. For a watch-only app, the watchOS state is “iOS app will be thinned.” For a watchOS app that has a companion iOS app, the state is either “iOS app is required” or “iOS app is optional.”
When your build is product quality, distribute it through the App Store. To create a watch-only app record, go to Add watchOS app information in App Store Connect Help. In the last sheet when uploading the build to App Store Connect, you can review the targets. For watch-only apps, the targets are: [Project Name], [Project Name] WatchKit App, and [Project Name] WatchKit Extension.
If you choose Ad Hoc, Enterprise, or Development as the distribution method, you can choose an Apple Watch device variant as the distribution option.
For projects you create using the “iOS App with Watch App” template, you can add support for running the watchOS app without the iOS companion app. To ensure your app runs independently, go to Creating Independent watchOS Apps.
In Xcode 11 and later, this feature is enabled by default.
In the project editor, choose the [Project Name] WatchKit Extension target, then click General.
Under Deployment Info, check the Supports Running Without iOS App Installation box.