Answer Description
Previously known as Windows Marketplace, the app and software store for Microsoft is now known as Windows Store. Update (Dec. 2017): Microsoft has renamed the Windows Store to the Microsoft Store. This question has been updated accordingly.
Wikipedia
Microsoft Store (formerly known as Windows Store) is a digital distribution platform sponsored by Microsoft. It started as an app store for Windows 8 and Windows Server 2012 as the primary means of distributing Universal Windows Platform (UWP) apps. With Windows 10, Microsoft merged its other distribution platforms (Windows Marketplace, Windows Phone Store, Xbox Video and Xbox Music and eventually Xbox Store) into Microsoft Store, making it a unified distribution point for apps, digital …
Microsoft Store (digital) - Wikipedia, the free encyclopedia