Thank you for asking this question on the Microsoft Q&A Platform.
The minimal license that you require to create a mailbox in Exchange Online (Plan 1) with this license you have:
- 50 GB mailbox and messages up to 150 MB
- Outlook on the web provides a premium browser-based experience
- Focused Inbox makes it easy to track email that matters most
- Automatically move old messages to an In-Place Archive
Learn more: https://www.microsoft.com/en-us/microsoft-365/exchange/exchange-online
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