User Configuration > Administrative Templates > Microsoft Project 2016 > Project Options > View
User
HKCU\software\policies\microsoft\office\16.0\ms project\options\view
Allows you to manage whether users can set the default currency type for their new project plans. If you enable this setting, the default currency type is enforced for all new project plans. If this setting is disabled or not configured, users can set the default currency type for new project plans.