A Data Exchange allows you to share portions of your model with other collaborators so they can complete their work without the need to share your entire Revit model.
3D views of a Revit model are used to make a Data Exchange. Data Exchanges are created using Autodesk Docs once the model is published. Specific 3D views from the model are selected and a Data Exchanges are created. The Data Exchanges are then used by collaborators to complete their work.
Using a Data Exchange allows you to share limited portions of the Revit model relevant to the collaborator's work. Because the entire model is not shared as part of the Data Exchange, processing and download times are considerably faster than workflows where the entire model is used for collaboration. Data Exchange recipients only receive information relevant to their scope of work.
For more information see: Autodesk Docs: Data Exchanges.