If you have connected banks that use foreign currencies, you can add transactions in a foreign currency to QuickBooks Online. 

Note: Foreign currencies are only available in QuickBooks Online Essentials and Plus

Add transactions in a foreign currency

You'll see currency fields when you open the transaction details and select Add.

Enter the Foreign amount or the Exchange rate, whichever your bank provides. QuickBooks will calculate the total. The Bank Description or Detail fields will display the transaction as your bank displayed it on your statement, usually with the amount and currency.

Split a transaction

If you are using a foreign currency, you can still split deposit and expense transactions based on different account categories and tax. However, you can't split a transaction based on different currencies.

How can I split a transaction between categories: Enter transactions with multiple accounts (split) directly into the register