By default Azure AD Connect will sync automatically every 30 minutes. There will be a time for some reason you’d need to force sync the directories on your on-premise Active Directory and Azure Active Directory such as a new user, a new distribution group etc. You can force sync the directories synchronization by using PowerShell command. However, you need to install Azure Active Directory PowerShell Module or by connecting to your Office 365 Exchange Online before your can use the command.
Step 1 (if you’re connected via Office 365 Exchange Online) otherwise skip this step.
Type the following command,
Run the following command, for Delta Sync which is for most common and used for most situations.
Start-ADSyncSyncCycle -PolicyType Delta
For Full Sync which is only necessary in some situations.
Start-ADSyncSyncCycle -PolicyType Initial
If you connected via Office 365 Exchange Online PowerShell command, you should remove your session
That’s it all you need to force sync your directories on-premise Active Directory with Azure Active Directory.