Microsoft Exchange Online is a hosted messaging solution that delivers the capabilities of Microsoft Exchange Server as a cloud-based service. It gives users access to email, calendar, contacts, and tasks from PCs, the web, and mobile devices. It integrates fully with Active Directory, enabling administrators to use group policies, as well as other administration tools, to manage Exchange Online features across their environment.
Office 365 is available in a variety of plans to best meet the needs of your organization. For information about different plans, including standalone plan options and information on moving from one plan to another, see Office 365 Plan Options.