Hello Fiona Hughe,
Thank you for posting your query in the Microsoft Q&A Community.
To achieve this, you can leverage on the Per-user MFA feature in Azure.
- Sign in to the Microsoft Entra admin center as at least an Authentication Administrator.
- Browse to Identity > Users > All users.
- Select Per-user MFA.
Follow this link for more information about this. https://learn.microsoft.com/en-us/entra/identity/authentication/howto-mfa-userstates#view-the-status-for-a-user
Let me know if you need further assistance.
Babafemi