User Configuration > Administrative Templates > Microsoft Outlook 2016 > Outlook Options > Preferences > Junk E-mail
User
HKCU\software\policies\microsoft\office\16.0\outlook\options\mail
This policy setting determines whether suspected junk e-mail is permanently deleted instead of moved to the Junk E-mail folder. If you enable this policy setting, suspected junk e-mail is immediately deleted and not moved into the Deleted Items folder. If you disable or do not configure this policy setting, suspected junk e-mail is moved into the Junk E-mail folder.