At this time, the feature to turn on payments by adding the pay button is unavailable for QuickBooks Online South Africa.
That would be a great addition to the current features that we have, so I'll take note of it. I'd also recommend visiting our Blog to learn what new updates and features we have.
Check the following article on how to create invoices in QuickBooks Online.
Also, you can find third-party apps that can integrate successfully with QuickBooks. See this article for more information: https://quickbooks.intuit.com/za/apps/.
Stay in touch if you have other concerns by leaving a comment below. I'm always glad to help in any way I can. Have a great rest of the day.
Consider having a 3rd party payment service. I noticed it supports QBO South Africa version.
You may also explore this 3rd paty app to deal with multi currency transactions.
Hope it helps.