Answer:
Lapel microphones are small wired microphones that are used for things like broadcasting and filmmaking. They are mostly used for recording dialogue as they are discreet and unobtrusive and can be very helpful when you need it to be out of sight, since it's small. They clip onto a piece of clothing on whoever the person wearing it is. The close proximity to the mouth is very helpful to stop other noises beside the dialogue or whatever the person is saying.
Omnidirectional microphone are used to pick up an equal amount of sound from all directions and sides. Whichever place a person is standing and speaking into it, the microphone will record it equally.