Which type of artifact in BPMN is used for adding notes to a process?

Annotations are specifically designed in BPMN to provide additional information about various elements within a process. They enhance the understanding of the process by allowing designers to add context, comments, or clarifications without impacting the actual flow of the process. This is crucial in collaborative environments where multiple stakeholders may need insight into specific decisions or components of the process without complicating the diagram itself.

In contrast, Data Objects represent data used or produced in the process, Groups serve to organize elements without affecting the process flow, and Flow Objects include the main components that drive the process, such as events, activities, and gateways. These other artifact types do not serve the purpose of adding commentary or explanatory notes, which is the primary function of Annotations in BPMN diagrams.