Customers are registered recipients of invoices, invoices can only be sent to an existing customer.

The company_type field of a customer determines the customer's legal status; whether they are a private person or a business, and whether they reside in the Billogram business account's country or not. This information controls the availability of some of the invoicing features, for instance the ROT/RUT deduction options are only available when a Swedish business is invoicing a Swedish private customer, not when they invoice a foreign customer or another business.