Yes, there is a mobile app available for managing a Starwood Preferred Guest account. This app is part of the Marriott Bonvoy app, which incorporates the Starwood loyalty program following the merger of Starwood Hotels and Marriott International. Through this app, members can easily manage their accounts, view their points balance, make reservations, and access exclusive offers. In addition, the app allows for convenient check-in and check-out processes, along with access to property information. To ensure you have the latest features and updates, it is advisable to regularly check for app updates through your device's app store. For more information, members might want to visit the Marriott website to see additional details regarding the app functionality and support.