OptionalfooterDefault invoice footer.
Optionalnext_Sequence number to use on the customer account's next invoice. Defaults to 1.
OptionalprefixPrefix used to generate unique invoice numbers. Must be 3-12 uppercase letters or numbers.
OptionalrenderingDefault invoice PDF rendering options.
The list of up to 4 default custom fields to be displayed on invoices for this customer. When updating, pass an empty string to remove previously-defined fields.