What doea "economy international shipping" mean from china to australia

I 'm wanting to buy an item from ebay and their shipping details states "economy international shipping "? Does this have a tracking number? Do you have to sign for it? I always prefer to pay extra to sign for my parcel. I have asked the ebay seller who is based in China but they don't understanding what I 'm asking. I tried looking up China Post Office but didn't find anything.
Can some please, please help me. Or advise me how to ask the seller so they understand me.
Thank you