MileagePlus X is a free-to-download iPhone app developed by Mileage Plus Holdings LLC. The app is designed to help you earn United MileagePlus® award miles for your everyday activities. The app features a rich selection of shopping, dining, and exclusive Cardmember offers. With MileagePlus X, you can search for your favorite restaurants and retailers to see all the current offers available across the entire app and earn miles while you shop or dine.

The app is easy to use, and the interface is user-friendly. The home screen displays the latest offers and promotions, and you can navigate through the app to find specific retailers or restaurants. The app also features a barcode scanner, which you can use to earn miles on the go by scanning the barcode on your receipt.

Overall, MileagePlus X is an excellent app for United MileagePlus® members who want to earn miles while shopping or dining. With a patent-pending feature, this app is a must-have for frequent flyers who want to maximize their earnings.