Every Microsoft 365 Access has ot be authenticated and authorized most the time and so we need an identity. But how are matching the piece together? Learn about Entra ID Member/External User/Guests, contact. How do we manage them with EntraID Sync, Cloud Sync, Cross Tenant Sync, PowerShell/Graph. Prevent duplicates, handle undeletes and matching, what happen with Tenant Migration, Why do Exchange properties and Teams phone numbers need special handlling. Let's talk about writeback, management of Groups, SCIM and other sync options for Apps and services.