Haven’t ordered from these guys before but preordered an item and purchased another item in pile of loot but i have a question about shipping

How dose FedEx International option ship
1)fully FedEx all the way ? (From America to Australia)
Or
2)uses USPS to ship to Australia ?
Or
3)FedEx all the way till it reaches Australia then uses Australia Post for final mile delvery?
If the 3rd option dose it tell you the Australia Post tracking no in tracking what was sent?

I’m just curious how is ships before choosing fedex option