@Kuronuma Thank you for reaching out to us, Please review this document - https://learn.microsoft.com/en-us/entra/external-id/b2b-tutorial-require-mfa In Microsoft Entra ID, you can accomplish this goal with a Conditional Access policy that requires MFA for access. MFA policies can be enforced at the tenant, app, or individual guest user level, the same way that they're enabled for members of your own organization.
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