@lgodlewski
As mentioned by @Carlos Solís Salazar Azure AD Connect can only sync from your local AD to Azure AD. There are some writeback features such as device writeback, group writeback, etc., but it isn't possible to create users in Azure AD and sync them back to on-premises AD.
I did find a Tech Community answer that might be a potential workaround where you can leverage Exchange Online to eventually setup your on-premises AD objects with the same UPN and SMTP addresses that are set in Azure AD. For more info - Azure AD sync to on premise AD.
If you'd like the feature of syncing from Azure AD to Local AD to be available, I'd recommend leveraging our User Voice forum and creating a feature request, so our engineering team can look into implementing this.
Additional Links:
Why use Azure AD Connect?
Topologies for Azure AD Connect
If you have any other questions, please let me know.
Thank you for your time and patience throughout this issue.
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