|Lapel Microphone with Earphone Jack|
The sound from a microphone near the presenter's mouth is better from that on a desktop computer. The lapel microphone can be secured to clothing, so it doesn't flap around, like those on earbud cables, being a distraction and making rustling sounds. Some prefer a wireless microphone, but that requires batteries which may fail. Also the cable stops you from wandering out of shot. ;-)
|Headset Splitter Adapter|
Most convenient I have found is to put the microphone and earphone cables down the inside front of my jacket, to the phone in a pocket. This way, if I need to I can get up and walk around. This is much as a lecture theater wireless lapel microphone is used, but the range is longer: anywhere the mobile network is available.