B2B Collaboration

Microsoft Entra B2B collaboration is the mechanism for inviting external partners — users from other Microsoft 365 tenants, Google accounts, personal Microsoft accounts, or even ad-hoc email addresses — into your tenant as guest users. The guest signs in with their home identity provider, your tenant trusts the authentication, applies its own Conditional Access on top, and grants whatever access you've configured. No new password is created in your tenant; if the user leaves their home company, their guest access naturally breaks. Configuration lives in Cross-Tenant Access Settings (CTAS). The right pattern for ongoing collaboration with people who aren't employees.