Office 365 Message Encryption is offered as part of Office 365 Enterprise E3 and E5, Microsoft Enterprise E3 and E5, Microsoft 365 Business, Office 365 A1, A3, and A5, and Office 365 Government G3 and G5. Customers do not need additional licenses to receive the new protection capabilities powered by Azure Information Protection.
You can also add Azure Information Protection Plan 1 to the following plans to receive the new Office 365 Message Encryption capabilities: Exchange Online Plan 1, Exchange Online Plan 2, Office 365 F1, Office 365 Business Essentials, Office 365 Business Premium, or Office 365 Enterprise E1.