1. Go to Setup, Settings, Company, then Currency.
2. Put a check mark in the option I want to enter transactions using Foreign Currencies.
3. Select a Home Currency.
   • If you can't access the option, you’ve posted transactions to the file
   • You’ll need to create a new file if you want to change
4. Go to the Enter information about your home currency section.
   • Select an Expense Account to Track Exchange and Rounding Differences in
5. In the Add or modify currency(s) used section select the Foreign Currency.
6. Fill in all other fields as necessary.
7. Optional: Enter an exchange rate for the new currency by clicking the Exchange Rate button. 
8. Select OK.
9. Create invoices using USD or other foreign currencies.

When adding a foreign currency, I can't find the denomination matching the foreign currency