You can add, edit, and delete view modes for entities on the <a href=":view_modes">View modes page</a>, and you can add, edit, and delete form modes for entities on the <a href=":form_modes">Form modes page</a>. Once you have defined a view mode or form mode for an entity type, it will be available on the Manage display or Manage form display page for each sub-type of that entity.