Account: can be understood as customers, the company can be organized, of course, can be personal
Contact: From the literal meaning for a contact
For example, Tencent buy our software, they are mainly responsible for the IT department pony, then Tencent to create into Account, to create a pony into contact
If their company as well as Zhang, Li, also can be used as a contact, they can create into contact.
connection relation:
Contact may be achieved by association Account Account Name field of the Contact, Account can have a plurality of contact
Account can be carried out by Primary Contact Contact associated with a same multiple Account and can also be associated with a Contact, for example, Tencent also have to use our software subsidiary, the company sent their son's pony is a unified contact, too That is, the primary contact for the pony Tencent, Tencent subsidiary primary contact is also pony
Reference documents: https://docs.microsoft.com/zh-cn/learn/modules/overview-d365-sales-professional/3-manage-your-customers