Open the App IDs page of your developer account.

Click + to create a new Bundle ID.

Enter an app name, select Explicit App ID, and enter an ID.

Select the services your app uses, then click Continue.

On the next page, confirm the details and click Register
to register your Bundle ID.

Create an application record on App Store Connect

Register your app on App Store Connect:

Open App Store Connect in your browser.

On the App Store Connect landing page, click My Apps.

Click + in the top-left corner of the My Apps page,
then select New App.

Fill in your app details in the form that appears.
In the Platforms section, ensure that macOS is checked.
Since Flutter does not currently support tvOS,
leave that checkbox unchecked. Click Create.

Navigate to the application details for your app and select
App Information from the sidebar.