Headphone Adapter

ive just purchased the iPhone 8 Plus, does this come with a headphone adapter, Apple say no but a friend of mine had one with his, and I also read on another Apple discussing board that there should be one with the headphone which came with the phone, nope, I have checked the entire box, not in there, so I’m a bit confused as been told by 2 different Apple representatives that there is and not included.