The Live E-Mail tile shows you an overview of the last unread e-mails from the account you are logged in with. Its possible to quickly write an E-Mail by clicking on the "+" icon.
From the live tile, you can open Outlook Web Access(OWA) directly or the Workspace 365 Email app, by changing the Destination in Apps Management.
To activate the app:
Change the tile format to 4 x 4 or higher to get live version.
When changed back to 2 x 2 or 1 x 1 format it will show the regular icon.