The Office app is essentially an app version of Office.com and becomes the replacement to the My Office app, a native app pre-installed on Windows.
The Office app is a central window to recent documents, contacts, and Microsoft apps such as Word, Excel, PowerPoint, Outlook, OneDrive, Teams, Yammer and so on.
But it's also a bridge between working offline and online using Windows 10. Users can both access Office desktop apps that are installed on the device and web apps on Office Online. It's also a window to locally stored files and files held in OneDrive and SharePoint.
Because it is a PWA, it works offline and can also be pinned to the taskbar, just like a native Windows app. However, users will need to be on Windows 10 version 1803 or later since only these versions support PWAs.
If an Office productivity app or service is installed locally, the Office app automatically launches the local version, and if it's not it will take the user to the web version.
The Office app also foregrounds recent and pinned documents and there's a Microsoft search field for quickly finding documents and contacts in an organization.
While it is available for consumers, Microsoft says the Office app has been built with organizations in mind. IT admins, for example, can customize the Office app with company branding, and allow users to access third-party apps through the Office app.
Windows 10 users with the pre-installed MyOffice app should see it replaced by the Office app in coming weeks through an automatic update, according to Microsoft. Otherwise it can be installed from the Microsoft Store.
Microsoft published a demo of the PWA Office app's offline capabilities on its Microsoft Mechanics YouTube channel. With the device in airplane mode, the Office app has already cached enough content to load with all the app icons and recommended documents intact. If documents in OneDrive are synced locally, users can still open the file from the offline Office app.
Aaron Gustafson from the Microsoft Edge browser team also gave an update on Edge and PWAs. Gustafson said the next version of Edge, which will be Chromium-based, will allow users to install PWAs directly from the browser, bringing it in line with Chrome and Firefox.
However, Gustafson pointed out that PWAs published to the Microsoft Store become "supercharged" since they have access to the same APIs that UWP apps have, as well as access to device hardware, such as the camera and Windows Hello authentication. An example was the Twitter PWA from the Microsoft store, which automatically switched to night mode if dark mode is enabled in Windows 10 settings.