Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi Giuseppe Mazzeo,
As I know, you may can use script to access the all Office 365 contacts, please see more information from: https://gallery.technet.microsoft.com/office/Access-Outlook-Contacts-7c2feb65 . From Office 365 PowerShell or Azure Active Directory PowerShell, we have no related article about get all contacts for users. If you have any further concern about above scrip, please go to script forum to get dedicated support: https://social.technet.microsoft.com/Forums/windows/en-US/home?forum=winserverpowershell
Meanwhile, we can only use Office 365 PowerShell to get mail contacts for all organization: https://technet.microsoft.com/en-us/library/aa998258(v=exchg.160).aspx
Thanks for your understanding.
Regards,
Richard