As an administrator, you can choose how feature layers and hosted feature layer views are shared with collaboration recipients. Sharing your layers and views as a reference provides recipients with live access to the shared layers as well as access to the feature layer's informational products, such as web maps and web mapping applications, if they have also been shared with collaboration participants.
When you share a feature layer or view as a reference, a new layer that refers to the source layer or view is created in each participating portal, rather than copying the source data. Edits made to the source layer in the originating ArcGIS Enterprise portal or ArcGIS Online organization are made immediately available to recipients. To access a feature layer or view shared by reference, participants must have access to the feature layer in the originating portal or organization, unless the layer is shared with Everyone. For secured layers, recipients will need to authenticate in the originating portal or organization as a member to whom the layer has been shared. Recipients must have, at least, a Viewer role to see secured content shared by reference. ArcGIS Enterprise to ArcGIS Enterprise collaborations can add Viewer credentials to a collaboration workspace for both host and guest participants. This allow recipients of services shared as references to view content without requiring credentials from the originating portal.
To share your layers and views as references, choose the As References option while joining a group to a collaboration workspace. All layers and views shared to this group will be shared as a reference, even if the original items are sync-enabled.