The Mac App Store is an application store on Mac OS used to purchase, download, install, and license applications. For more information, visit http://www.apple.com/mac/appstore/.
Your Creative Cloud subscription comes with Lightroom on desktop, Lightroom mobile (iOS and Android), access to lightroom.adobe.com, and 1 TB of cloud storage.
You can buy Lightroom from either Adobe.com or Apple’s Mac App Store. It is the same app. However, it is not recommended to install both versions at the same time. Keep the version installed from the store where you purchased the app to ensure timely communication about updates.
You can check your plan to identify the store from where you purchased Lightroom.
The Mac App Store will send you an update notification, and will provide you with the latest version of Lightroom desktop through the Mac App Store.
Any Lightroom subscription that you purchase from the App Store is managed by Apple. You can cancel your subscription using the App Store app.
For step-by-step instructions, see Apple documentation for View, change, or cancel your subscriptions.
For billing issues or a refund, see Apple documentation for Request a refund for an App Store or iTunes Store purchase.