Multifactor authentication and Privileged Identity Management
We recommend that you require multifactor authentication (MFA or 2FA) for all your administrators. Multifactor authentication reduces the risk of an attack using a compromised password.
You can require that users complete a multifactor authentication challenge when they sign in. You can also require that users complete a multifactor authentication challenge when they activate a role in Privileged Identity Management (PIM) in Azure Active Directory (Azure AD), part of Microsoft Entra. This way, even if the user didn't complete multifactor authentication when they signed in, they'll be asked to do it by Privileged Identity Management.
Right now, Azure AD Multi-Factor Authentication only works with work or school accounts, not Microsoft personal accounts (usually a personal account that's used to sign in to Microsoft services such as Skype, Xbox, or Outlook.com). Because of this, anyone using a personal account can't be an eligible administrator because they can't use multifactor authentication to activate their roles. If these users need to continue managing workloads using a Microsoft account, elevate them to permanent administrators for now.
How PIM validates MFA
There are two options for validating multifactor authentication when a user activates a role.
The simplest option is to rely on Azure AD Multi-Factor Authentication for users who are activating a privileged role. To do this, first check that those users are licensed, if necessary, and have registered for Azure AD Multi-Factor Authentication. For more information about how to deploy Azure AD Multi-Factor Authentication, see Deploy cloud-based Azure AD Multi-Factor Authentication. It is recommended, but not required, that you configure Azure AD to enforce multifactor authentication for these users when they sign in. This is because the multifactor authentication checks will be made by Privileged Identity Management itself.
Alternatively, if users authenticate on-premises you can have your identity provider be responsible for multifactor authentication. For example, if you have configured AD Federation Services to require smartcard-based authentication before accessing Azure AD, Securing cloud resources with Azure AD Multi-Factor Authentication and AD FS includes instructions for configuring AD FS to send claims to Azure AD. When a user tries to activate a role, Privileged Identity Management will accept that multifactor authentication has already been validated for the user once it receives the appropriate claims.