OptionalbusinessDestination shortcode. Defaults to config.shortcode.
yyyymmdd.
StandingOrderName — must be unique per customer (duplicate → 1050).
Customer M-Pesa phone 2547XXXXXXXX (PartyA, the payer).
yyyymmdd.
Comment. Max 13 chars.
Paybill or Buy Goods. Sets TransactionType + ReceiverPartyIdentifierType.
Account number for the paybill. Max 12 chars.