Dashboards can either be private or shared.
If a dashboard is set to Private, then only the dashboard creator or a system administrator can view and edit the dashboard.
If a dashboard is set to Shared, then every user with proper access can view the dashboard. For users to have proper access, they must have an active account on the dashboard application and have been granted access to each profile that the dashboard contains. Aside from administrators, other users cannot permanently edit dashboards that they did not create. Users can, however, make edits and save the dashboard as a copy.