The owner user type can:

Simulate all users created from his/her organization and sub-organization (if it has) if it is active unless Support.
Access the sections of Campaigns, Analytics, Creatives, Audiences, Audience Insights, Geolists, Deals, Publishers, External Campaigns, Tracking events, Organization
Activate/deactivate fields with additional cost (premium features enabled by Owner).
View and manage the premium fields enabled and signed by contract by an Admin. These premium fields (with additional cost) become FREE for that organisation if the Admins allow it.
Create and edit users.

Owners receive notifications if an Owner or an Admin activates/deactivates premium features within the Organizations section or within a single campaign, for example.
Owners do not receive notifications about the changes from an Editor.
Owners can activate/deactivate many notifications in their settings.

Owners can manage users, sub-organizations and deals.
Owners can access, view and manage basic fields activites by an Admin.
Owners can access, view and manage ALL fields with premium features by Owner.
Owners can view and manage the premium fields enabled and signed by contract by an Admin.
Owners can create users in your organization only if the organization is active:

Owners can activate/deactivate fields at additional cost (premium features enabled by Owner).
Owners can view and manage the premium fields enabled and signed by contract by an Admin. These premium fields (at additional cost) become FREE for that organisation if the Admins allow it.
Owners can view and manage all campaigns from their organizations and sub-organizations (if it has one).
Owners can view all campaigns in their organization but can ONLY configure the campaigns that you have created or that have been assigned by other Owners.
A new campaign created by an Owner automatically is not assigned to any user.

Introduction to the different User roles