TL;DR:
On 12th October 2022 Microsoft announced that the Office app for web (office.com), Windows, iOS, and Android will be rebranded to become the Microsoft 365 app. Between late 2022 and early 2023, these apps will automatically update to the Microsoft 365 app and include a new icon, styling, and features. 

Details:
Office web app (Office.com): Changes will begin rolling out in November 2022. This will be part of a phased rollout, so not everyone will receive the update at the same time. You can experience the new experience at microsoft365.com. In mid-2023, office.com will begin automatically redirecting to microsoft365.com.

Office mobile apps for iOS, Android and the Office app for Windows users will begin seeing in-product messaging from November 2022 notifying them of the upcoming change. In January 2023, these apps will automatically update to become the Microsoft 365 app. When that update occurs, you will see the new Microsoft 365 icon on your device screens instead of the current Office icon.

Image snippet from Microsoft FAQ, see below link.

“The Microsoft 365 app is an evolution of the current Office app. Existing users will be familiar with many of the core experiences. The app provides a single destination for users to find all their content across multiple file types and storage locations, start new files in the Create module from a wide variety of apps and templates, and find all the applications entitled to them through their Microsoft 365 plan”.

New features:

  • Feed – a new page that uses intelligence from the Microsoft Graph to surface relevant content based on who you work with and what you do
  • Tagging (web and Windows only) – a new feature that helps you individually group content with custom “tags”, regardless of where the content is stored
  • Apps module – a new apps module connects users to Microsoft 365 apps beyond Word, Excel, and PowerPoint, including third-party apps that have integrated with Microsoft 365

Availability:
The changes will roll out between late 2022 and early 2023.

Source, related links, and references:
MC446132 
FAQ: Microsoft Office is changing to Microsoft 365

Check status:
Microsoft 365 Roadmap ID 98173

Page originally published:
29th October 2022 and kept up to date.