HeroMart can only receive an order from a customer, they cannot charge any extra fees that are required to be paid to the payment processor, the specific country, state, province, or city you live in, or any other kinds of required fees. These kinds of fees include customs fees, duties fees, US state tax, or VAT (value added fees if you are in the EU.)
HeroMart is not responsible for charging or paying any of these fees, it is the customer's responsibility to pay them to have their order shipped and delivered properly. HeroMart also has no control over currency conversion rates.
Please refer to the this help page for more information about shipping cost/times.
You can always contact Artix Support if you have any questions!