seen here on December 11, 2017
Now you can make your new apps available for pre-order on all Apple platforms. Customers can see your product page and order your app before it's released for download. Once your app is released, customers will be notified and your app will automatically download to their device. For paid apps, customers will be charged before download.
To make your new app available for pre-order:
From the homepage, click My Apps, select the app, and select Pricing and Availability in the left column. You'll see the Pre-Orders section if your app has never been published on the App Store.
Select Make available for pre-order, choose a date to release your app for download, then click Save in the upper-right corner. The release date must be at least two days in the future, but no more than 90 days in the future.
Submit your app for review.
Once your app is approved and you're ready to make it available for pre-order, return to Pricing and Availability, confirm the date your app will be released for download, and click Release as Pre-Order in the upper-right corner.
You can submit a new version update or change pricing and availability during the pre-order period. If you change the price of your app during the pre-order period, customers will be charged the price that is lower — the price they accepted for pre-order or the price on the day of release. If your app offers in-app purchases, you can set them up in iTunes Connect before and during the pre-order period so that everything is ready once your app is released for download. Keep in mind that promoted in-app purchases will not display on your App Store product page until your app is released for download.
Learn more about setting up pre-orders in iTunes Connect.
Learn about tracking performance for your pre-orders.