If your appointment was scheduled through National Visa Center (NVC), you have generally already paid your visa fee.
Required immigrant visa fees may be paid at the Embassy or Consulate in cash (in U.S. dollar or Indian Rupee) or by a rupee bank draft drawn on a nationalized or foreign bank. The bank draft must be issued in the name of “The American Embassy, New Delhi”, and should be payable in Delhi OR in the name of “U.S. Consulate General, Mumbai” and should be payable in Mumbai. The U.S. Consulate General, Mumbai also accepts credit card payments for immigrant visa fees.
As the consular rate of exchange can change, check the current consular rate of exchange here the day prior to your interview to obtain the current consular rate of exchange. Please note that visa fees are not refundable.