If you're referring to assigning a foreign currency to a customer, yes you can use the USD currency as a functional one in QuickBooks Online Hongkong region. You'll need to create a new customer profile and choose the foreign currency that they use to pay you for products or services. Then, create the transaction and assign the USD currency to your customer.
One problem that you might run into is that QBO reporting for multi currency is pretty limited. There is no way to report on the foreign balance of an account that has a currency different than your home currency. The only way to report the value is in the home currency but this is often not what is needed.
Unfortunately the answer that was given was incorrect and made false assumptions about how the balance sheet detail report works for foreign currencies. In the other post it was suggested that you could manually calculate the ending foreign balance from a balance sheet detail report. Actually, that is incorrect information. It is not possible to manually calculate it from the report because there is no exchange rate for the beginning balance on that report. If you can't calculate the beginning balance in the foreign currency from the report then how can you use math to calculate the ending balance in a foreign currency?
