from the spec of the phone
https://www.apple.com/iphone-8/specs/
In the Box
iPhone with iOS 11
EarPods with Lightning Connector <--- this connect to the bottom connector you also charge with
Lightning to 3.5 mm Headphone Jack Adapter <-- this too and let you connect normal 3.5mm minijack headsets
Lightning to USB Cable
USB Power Adapter
Documentation
if your phone did not come with the listed items you should return it to where you purchased it