Microsoft (Office 365_E3 Plan) – Office 365 E3 Plan
Exchange Online – Cloud-based email 50GB of storage space per user, unlimited storage in the user

Microsoft (Azure Active Directory Rights Management) – Additional Plan
Azure Active Directory Rights Management
Azure Active Directory Rights Management enables a User to create and consume protected content. User has the ability to assign rights restrictions to email or documents (in Exchange and SharePoint Online for V1) and send it to anyone. Anyone has the ability to receive, view and reply to restricted content from another User. Admin has the ability to assign licenses, configure templates and mange encryption keys