If you need to manually run a sync cycle, then from PowerShell run Start-ADSyncSyncCycle - PolicyType Delta. To initiate a full sync cycle, run Start-ADSyncSyncCycle -PolicyType Initial from a PowerShell prompt. Running a full sync cycle can be very time consuming, so if you need to replicate the user information to Azure AD immediately then run Start-ADSyncSyncCycle -PolicyType Delta. Reference: https://docs.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-sync-feature-scheduler