Pre-Orders (App Store) are an App Store option that publishes an app's product page before release, so people can order it in advance and have it download automatically to their device on launch day.
A new app can go on pre-order once it has been through App Review, with a release date 2 to 180 days out; an app already live in at least one region can open pre-orders elsewhere up to 365 days ahead. Pre-order pages are discoverable in search and can be promoted with Apple Ads. Customers aren't charged for a paid app until release, and on launch day it downloads automatically to the device used to pre-order, with a notification. Google Play's counterpart is pre-registration, which runs for up to 90 days and auto-installs the app on eligible devices at launch.
The ASO case for pre-orders is timing. They turn weeks of demand into downloads on a single day, and in our experience that concentrated launch-day volume gives a new app stronger early ranking momentum than the same demand spread thin, though Apple doesn't document how pre-orders count toward charts. The pre-order period also works as a rehearsal: metadata and creative are live before launch, so teams can check search visibility and refine the page while stakes are low. Apple doesn't notify pre-order customers of date changes, so a slipped launch needs the developer's own communication.
Example
A puzzle game opens pre-orders 60 days before launch, points Apple Ads campaigns for its genre keywords at the pre-order page, and files an App Launch featuring nomination. On release day, pre-ordered copies download automatically, giving the game a concentrated first-day spike.