an identifier you can create to use in place of

This is an internal identifier for a customer that may be associated with the billing information of a transaction. This field may contain any format of information.

The 10-digit number, unique to the service, used to identify your organisation.

Your Customer ID is your 10-digit phone number (area code and 7-digit phone number). This number is located on the top right of each page of your bill.

A unique identification value assigned to a customer by a merchant, which may be associated with the invoicing or billing for a transaction.