Each user gets 50 GB of mailbox storage and can send messages up to 150 MB in size 
Users can connect supported versions of Outlook to Exchange Online, so they can use the rich client application they already know 
For web-client access, Outlook on the web provides a premium browser-based experience that matches the look and feel of the full Outlook client 
The Focused Inbox makes it easy to track email that matters most. Your inbox includes two tabs: Focused, for email you need to act on right away, and Other, for everything else. You can switch the tabs at any time and always see email flowing into Other 
Compare calendars to schedule meetings and access collaboration features, including shared calendars, groups, the global address list, external contacts, tasks, conference rooms, and delegation capabilities 
Every mailbox is protected with premier anti-malware and anti-spam protection via Exchange Online Protection 
Keep your inbox clean by automatically moving old messages to an In-Place Archive