asking this after searching without specific topic/answer.
I am gonna implement paypal express checkout to deal with customers paying by credit card. They request the support of level 2 credit card processing to upload such as customer id. Failing to find right answer in paypal doc or here, I only find ( Submitting Purchasing Card Level 2 and 3 Transactions ) in paypal doc, which I think is not for credit card.( https://developer.paypal.com/docs/classic/payflow/integration-guide/#submitting-purchasing-card-level-2-and-3-transactions )
Does anybody can help with piece of information/doc ? Very appreciated!