Sharing and Collaboration
Sharing questions test how content moves from your project to ArcGIS Online, ArcGIS Enterprise, or packages, and who can access it. Know the sharing targets: a web map or web layer hosted in a portal, a project package (.ppkx) that bundles maps and data for offline handoff, and layer packages or map packages. Publishing a feature layer creates a hosted service; the source data is copied to the portal unless you publish a reference to registered data.
Understand sharing levels: private (owner only), shared with groups, shared with the organization, and public (everyone). A trap is assuming sharing a map shares its layers; each item has its own sharing settings, and a map referencing a private layer will not display for others. Also know that overwriting a hosted layer updates the service while preserving its item ID and sharing settings.
Collaboration features include groups, projects with shared update, and branch versioning for multiuser editing in enterprise geodatabases. Credentials matter: stored credentials in a project can expose access, and publishing to a federated portal uses portal accounts.
Worked example
You publish a feature layer and share the web map with your organization, but a colleague cannot see the data. Rule of thumb: share the layer item and the map item, and confirm the layer's sharing level matches the map's. If the layer is private, the map appears empty for others.
Other traps: confusing a package (portable, offline) with a published service (live, portal-hosted), and forgetting that public sharing exposes data to everyone, not just your organization.