Depending on how much you wish to spend, there are several ways.

China Postal Services has an expedite service, which you also can register and insure, and it is not too expensive for documents.  I have used it, and mine always have arrived.  Locally in China about 3 days maximum, overseas about two weeks.

And then, of course, you do have the other traditional international carriers, like Fed EX, UPS and DHL.  Their service is probably faster, and lots more expensive/  And some do have peace of mind by thinking that because they are international, whatever is mailed will not be lost.  But in my experience, it could happen with any carrier.

You would need to do some leg work and find within those mentioned which one you fancy.