Office 365: Sharing
The configurations and set up that we just walked through can be customized in the Office 365 Admin Center.

Before You Begin: If you have not already done so, please return to Office 365 online.
Go to Home->Outlook.

1. Try It: Find the Sharing Overview
Go to Home->Admin->Office 365.
Click on External Sharing.

What Do You See? The Sharing Overview shows that Sharing is "On" for:
Sites
Calendar
Lync

Keep going...

Home->Admin->Office 365->External Sharing