What is 365 3.?

As an AI language model, I am not sure what exactly you are referring to when you say "365 3". However, if you meant Microsoft Office 365, it is a subscription-based online suite of popular productivity tools such as Word, Excel, PowerPoint, Outlook, OneNote, OneDrive, SharePoint, and Teams. The suite can be accessed through a web browser or installed locally on computers and mobile devices, and provides features and updates regularly.

If you meant something else, please provide more details about the context so I can provide a more accurate answer.