Azure AD Connect: Migration from Passthrough Authentication (PTA) to Password Hash Synchronization (PHS)
Migrating from Passthrough Authentication to Password Hash Sync (PHS) synchronizes passwords from the on-premises Active Directory instance to Azure AD. This is a considerable gain in convenience for users. From now on, they can sign in with the same credentials (user name, password and optionally with multi-factor authentication).This increases productivity and at the same time reduces user support costs.