Establish contact with the customer 

Definitions of a customer

A customer (also known as a client, buyer, or purchaser) is the recipient of a good, service, product, or idea, obtained from a seller, vendor, or supplier for a monetary or other valuable consideration. 

Classification of customers 

Customers are generally categorized into two types: 

• An intermediate customer or trade customer (more informally: "the trade") who is a dealer that purchases goods for re-sale. 
• An ultimate customer who does not in turn re-sell the things bought but either passes them to the consumer or actually is the consumer. 

Customers also can be classified as internal and external customers: 

• Internal customers are people from within your organization who need your assistance. 
• External costumers are people from other organizations who come for as recipient of a good or service.