A payment instrument is a form of payment your business will accept in exchange for goods and/or services. The payment instrument user-defined code table (00/PY) indicates various methods of payment such as draft, check, and electronic funds transfer. You assign a payment instrument code to each invoice or voucher.  Therefore, you will need a code for each type of payment instrument that you want to use.  Prepayment processing is driven by the value in the special handling code column. Therefore, to identify PayPal® Payments (Express Checkout) transaction payment instruments you must use payment types with assigned special handling code of (1SCP) as illustrated below.