When creating or editing a customer, there are two ways in which a customer can be billed: Directly, or through Parent Billing.
All invoices issued on any charges incurred by the customer will be created against the customer's billing address. In the case of invoice delivery, if the delivery type is email, the customer will directly receive invoices as attachments.
If a customer is not set to be billed directly, a parent customer must be chosen as the billing entity of any charges incurred. Any charges applied against the customer's ledger will be invoiced to the parent customer, and the charges will appear within the parent customer's invoices, under a specific heading indicating which child company incurred the charges.