NACHA (the regulatory body governing the ACH network) requires that API callers
(merchants, partners) obtain the consumer’s explicit authorization before
initiating a transaction. To stay compliant, you’ll need to make sure that
you retain a compliant authorization for each transaction that you originate
to the ACH Network using this API. ACH transactions are categorized
(using SEC codes) by how you capture authorization from the Receiver
(the person whose bank account is being debited or credited). PayPal
supports the following SEC codes.