Dynamics 365 Marketing is a marketing-automation application that helps turn prospects into business relationships. The app is easy to use, works seamlessly with Dynamics 365 Sales, and has built-in business intelligence. More info on https://dynamics.microsoft.com/en-au/marketing/overview/
This is my first draft of the Dynamics 365 Marketing - Conceptual Diagram.
Use this diagram to get a shared understanding of the high-level features required by your system to meet your client requirements.
Check out my article about the "Conceptual Diagram" which is a key document I use to foster a shared understanding of the requirement and the solution we are building.