Stamping fee is the fee that the applicants have to pay for the Government at the airport to enter Vietnam. The payment is cash and paid directly at Immigration Counter in every international airport.
So, please prepare money in cash for stamping fee when you pick up your visa at Vietnam airport about:
Once again, you must paid in cash and prepare cash for this amount because you can not pay by credit cards for this amount at the airport & there is no ATM in this area at the airport.
Have a nice day!
Vietnam Immigration Team