Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Dear @Md. Towhidur Rahman,
Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, your institution already has an Office 365 A1 (Faculty) free plan, but when you try to add A1 student licenses, Microsoft shows that the domain is already owned by another account (also yours) and does not provide any student trial option. When signing in with the existing tenant, only the faculty plan appears. You wonder how you can enable or assign Office 365 A1 licenses for students within the same tenant.
Since your domain is already verified and linked to an existing Microsoft 365 Education tenant, student licenses cannot be activated through the Education free trial page. Office 365 A1 student licenses are automatically available within the same tenant as faculty licenses and can be assigned directly from the Microsoft 365 Admin Center by creating student users and assigning the A1 license.
Besides that, here are some suggestions you can try:
Sign in to the existing tenant, use the account that already has Office 365 A1 for Faculty.
Go to Billing > Licenses
You should see Office 365 A1 listed there.
Create student accounts
Create users with a student identity, for example: ******@yourdomain.com
Then assign the Office 365 A1 license to them.
Set the Education Tenant Identifier
For reference Tenant setup and deployment guide for Microsoft 365 for education baseline configurations
I hope information above meet your expectations. If not, please feel free to reach out so I can support you more effective.
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