We're unable to import the invoices and bills to affect your Accounts Receivable and Accounts Payable accounts, info213.

If you're still starting and you don't have transactions under your customers and suppliers, you can enter their individual balances in their profiles. Please refer to the screenshots. 

Here's an article for your additional reference: How to set up customer or supplier opening balance.

Alternatively, you can find a third-party app to import your transactions into QuickBooks. Just follow this link: https://apps.intuit.com/app/apps/home. Change the flag Australia and search for an app. You can try something like transaction importer, import, etc.

Feel free to reach out if you have other questions.