Prepaid foreign exchange means that the goods are not imported and foreign exchange will be paid without customs declaration. Prepaid foreign exchange needs to be applied in the online service platform of SAFE first, then paid in the bank after confirmation by SAFE, and the goods are cancelled online after being imported with the customs declaration form.
Post-payment means to get the customs declaration form and pay the remittance directly to the bank. When you pay the remittance, the bank will directly write it off for you, and you don't have to do anything.
Import value-added tax is directly deducted from the IRS.