If you’re using a Chromium browser like Chrome or Brave, then the support is live right now.
Microsoft has been slowly adopting PWAs for Windows apps since last year, and Outlook is a sign that we may see similar apps for the company’s other Office products like Word and Excel. PWAs, by their nature, are essentially still websites, but they include better caching, notification features, and background functionality to make them appear more like traditional apps. It’s a useful alternative to the cluttered Outlook Windows desktop app or the Windows Mail client that ships as part of Windows 10. This allows any Outlook user to install the web app into Windows, macOS, Chrome OS, and other platforms that natively support PWAs.
Microsoft is turning its and Outlook for the Web mail services into Progressive Web Apps (PWA).
