A Customer Address is an address belonging to a customer, with the usual address fields plus a phone number, names, company, a type, and primary-billing / primary-shipping flags. Other systems call it a Contact Address or Billing/Shipping (Bill-To/Ship-To Address).

This is where a customer's contact detail and phone number are stored - so a source system that puts phone on the customer record should map it to the customer's primary address. A customer can hold several addresses, and billing versus shipping is expressed by the type and the primary flags rather than by separate record types.