Hi there,
I know how important it is to work with a software that's flexible enough to handle various types of business transactions. An FX transaction deals with foreign exchange, and luckily QuickBooks Online has an awesome way to account for that in your books. I'll explain more about the Multicurrency feature.
Multicurrency is available in QuickBooks Online Essentials and Plus. If you do have reason to turn Multicurrency on, it can be a powerful feature for your business. Once on, QuickBooks Online downloads exchange rates nightly from WSoD (Wall Street on Demand). You can also manually enter exchange rates and revalue them if needed.
Here's everything you need to know about Multicurrency: About Multicurrency.
Based on your example, it sounds like you're billing in one currency, and accepting payment in another. This will definitely cause discrepancies in your books, as the totals won't match and you'll be left with open balances.
I want to make sure you're given the right information to handle this complex transaction. In this case, I'd encourage you to first consult an accountant to find out the best way to record this transaction. If you're not yet connected to an accountant, you can find one here. Then, you can reach out to our tech support team for help in recording the transaction based on your accountant's advice.
The steps you'll take will largely depend on how you're creating the transactions, what currencies are involved, and your accountant's professional advice. I hope this helps get you started on the right track.
Cheers.