
Named user entitlements
Licensing for ArcGIS Enterprise 10.5.1 is like licensing at 10.4. With your purchase of ArcGIS Enterprise is included a set of named user entitlements to be used within Portal for ArcGIS. A named user is a specified user for running ArcGIS Pro or a Premium App through ArcGIS Online of Portal for ArcGIS. The number of entitlements you receive depends on the edition and level of ArcGIS Enterprise purchased by your organization. Named user entitlements also differ for licensing under an Enterprise Licensing Agreement (ELA), education site license, or any other special licensing agreement with Esri.
The following are the named user entitlements:

Level 1 (L1) users are content viewers who can only view content shared with them through the organization. L1 users cannot own items or edit items. Level 2 (L2) users can view, create, edit, and share content and can be assigned into the Portal roles of User, Publisher, and Administrator. L1 access is no different than public anonymous (Share with Everyone), but allows named users to participate in focused sharing through groups.