How to choose currency for dropshipping in a different country?

[smhyderabadi]

Hi,
I am confused between choosing the currency as per billing address on shopify store! 
For example, I am currently living in Pakistan, but I want to sell products through dropshipping in United States, but I don't have any physical address or office in the United States, so what I am supposed to do? Is it necessary to have office in country where my main market will be (U.S in this case) ? Because if I will put my country in the billing preference/setting on the shopify store then the price will be displayed in my currency not in USD which will disappoint the customer and also returning the items will be difficult for customer.
Kindly help me, Thanking in advance.