Many people are receiving an email supposedly from FedEx similar to the ones listed below:
BillingOnline@fedex.com Pay your Fedex invoice online.
BillingOnline@fedex.com Your Fedex invoice is ready.
These are NOT legitimate emails; any attachment or links associated with the emails are designed to either infect your computer with malware or attempt to gain information about you. If you are expecting an invoice from FedEx or any other type of communication from them, verify over the phone the email address that your corresponding email will be coming from, and that the invoice number is correct.