How to: Forcing Azure AD to Sync with On-Premise Active Directory 

1. Reduce sync intervals by changing the Default 3 hour
    
2. Forcefully sync data with Azure AD and PowerShell 

This demo uses an on-premise AD server running Windows Server 2016 TP4.

Option 1: Changing  Default Sync Schedule

1. Log on to the On-premises AD server that contains the AD sync tool installed as Domain/Enterprise admin
2. Navigate to > Task Scheduler > Azure AD Sync Scheduler

3. Double click on the schedule > triggers tab. Double click on trigger to edit and define the time to sync.

4. When you save it will ask which user account to use for the job. You can define service account to run this task.

Option 2: Forcefully sync data with Azure AD and PowerShell 

1. Log on to the On-premises AD server which have AD sync tool installed Domain/Enterprise admin and load the PowerShell with admin privileges

2. Change directory to C:\Program Files\Microsoft Azure AD Sync\Bin

3. Run .\DirectorySyncClientCmd.exe which will run the sync

Source: CANITPRO