In Short

The Facebook App for Windows Phone is developed by Microsoft for the Windows Phone operating system and runs on Windows Phone 7.x and 8.x. Although the app is developed in-house by Microsoft, Facebook does contribute to the app through direct collaboration.

The Facebook App has a mixed record on performance, features and stability when compared to similar apps on other platforms. In response to this negative reaction, Microsoft has opened up access to their Facebook Beta app, which is the same app at a more advanced stage of development. Functionally, the apps are usually similar with the beta often outpacing the official release by a few weeks.

The Facebook App lets users "see what friends are up to; share updates, photos and videos; get notified when friends like and comment on your posts; Chat and have group conversations. Facebook notifications for new events are configurable by the user and tie into the Notification system found on Windows Phone.

Microsoft solicits feedback from consumers about the app through their dedicated User Voice page, found here:

The app can be downloaded to Windows Phone through this universal link or by scanning the QR code in the upper corner.