Of course the attached shipping label was a virus. Similar scams have used UPS, FedEx, and DHL logos. If you click on the file ("shipping label") your computer will become infected.
If this had been from the US postal service, the email address would have ended in "USPS.com". Instead it was something like "PrinceOfKenya@yohoo.it" or "OfficialGovernmentMailI'mNotKidding@yahoo.it"
So be warned. If you get a mail like this trash it. It's as bogus as Hillary Clinton's smile.