Hi there, jncnyaboke.
Our multi-currency option is available in some of our QuickBooks Online plan such as Essentials, Plus and Advanced, and in all Desktop versions. While we're unable to do that in QUickBooks Self-Employed, we can manually convert the amount before we record them. You might also want to use third-party apps that can help us use multiple currencies.
You can check out these links for more details on how this works in our other QuickBooks version:
I'll surely send this as feedback to our Product Development team and they might add it into one of QuickBooks Self-Employed feature updates.
Let me know if there's anything else you need help with. Take care!