Thanks for getting back to us, SP-1.

Yes, you can use third party application to help import sales receipts and expenses in QuickBooks Online. However, we're unable to recommend which app to use. I recommend checking in the Intuit App Center to help check supported applications in QuickBooks Online Australia.

Furthermore, for expense receipts we can use the receipt capture option in QBO. Check this link for reference: Upload your receipts to QuickBooks Online.

Post again in the Community if you have other questions.