DG is correct...

Youre assuming Paypal collects GST. They dont. Papal Australia is GST free. They only provide a funds transfer service and no financial institution pays GST on those services.
You cannot get a tax invoice from someone who does not collect tax 🙂
Hence, downloading your Paypal history is exactly what you would do.

Also, do NOT try to claim on the GST if there is none.. it **bleep** off the ATO.