The Live E-Mail tile shows you an overview of the last unread e-mails from the account you are logged in with.
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 to get live version.
When changed back to 2 x 2 or 1 x 1 format it will show the regular icon.