The connections provide a flexible way to connect and describe the relationships between any two entity records Dynamics 365 for Customer Engagement apps. It helps you to promote teamwork, collaboration, and effective management of business and sales processes. Connections enable you to easily associate users, contacts, quotes, sales orders, and many other entity records with each other.
The records in the association can be assigned particular roles that help define the purpose of the relationship.You can describe the relationship between records through the roles that you assign to them.
For more information, check the following video: