IOS – Select the availability date for the first release of an iOS app

Nowadays, apps submitted to the App Store will take 6 to 8 days to be reviewed based on how many apps are queued for review.

If your application is showing the status Waiting for Review, it means your app is not yet reviewed by Apple. Once the review process has started, your app will show the status Under Review.

Updates and new releases follow the same rules.

You can also refer here.

You can set the release date through iTunes Connect.

The App Distribution Guide in the iOS Developer Documentation has a page titled Managing Your App in iTunes Connect, where the section Changing the Availability Date of Your App states:

Use iTunes Connect to set a date when the app is available on the store. For example, you can choose a date that immediately releases the app to the store after it’s approved, or you can set a later date. Using a later availability date allows you to arrange other marketing activities around the launch of your app.

1. Sign in to iTunes Connect.

2. Select Manage Your Apps.

3. Select your app in the Recent Activity section.

4. Click Rights and Pricing.

5. Choose a date from the Availability Date pop-up menus.

6. Optionally, edit the other fields in this form.

7. Click Save.

Changes you make to Rights and Pricing go live immediately (expect 24 hours for a full refresh of the changes on the store).

Read the App Distribution Guide for more information on managing your app on the App Store.