Microsoft account (MSA) identity provider for External Identities (Preview)
Your B2B guest users can use their own personal Microsoft accounts for B2B collaboration without further configuration. Guest users can redeem your B2B collaboration invitations or complete your sign-up user flows using their personal Microsoft account.
Microsoft accounts are set up by a user to get access to consumer-oriented Microsoft products and cloud services, such as Outlook, OneDrive, Xbox LIVE, or Microsoft 365. The account is created and stored in the Microsoft consumer identity account system that's run by Microsoft.
Guest sign-in using Microsoft accounts
Microsoft account is available in the list of External Identities identity providers by default. No further configuration is needed to allow guest users to sign in with their Microsoft account using either the invitation flow or a self-service sign-up user flow.
Microsoft account in the invitation flow
When you invite a guest user to B2B collaboration, you can specify their Microsoft account as the email address they'll use to sign in.
Microsoft account in self-service sign-up user flows
Microsoft account is an identity provider option for your self-service sign-up user flows. Users can sign up for your applications using their own Microsoft accounts. First, you'll need to enable self-service sign-up for your tenant. Then you can set up a user flow for the application and select Microsoft account as one of the sign-in options.