When you add a customer in CertCapture, you must enter a customer number. This is a unique identifier for the customer, and generally corresponds to a similar identifier in your business application.
A customer number is the unique ID your business application uses to identify a customer or vendor. These IDs are linked to exemption methods in your business application, AvaTax, or CertCapture. The CertCapture customer number field corresponds to the AvaTax customer code field.
In CertCapture, the character limit for the CustomerCode field is 50.