What do you mean, customer?

What is a customer? How do customers know all aspects of the project they want to do when they come to the hospital? For example, the level of doctors, the safety and effect of surgery, and the cost. These are all explained by the client to the client. Most of the clients are nurses with several years' working experience and certain medical knowledge. Often eloquent, few customers are not tempted. The doctor is only responsible for the operation, and the client can only decide to do the project if he meets with the client. This is both two-dimensional