There are a ton of options when choosing a microphone for events and presentations.
Wired microphones are the ones that use a wire running from the microphone and connect directly into the audio system.
A handheld microphone will need to be held in one hand while the presenter is speaking (as the name suggests).
There are various types of frequency bands that are used. Very High Frequency (VHF) and Ultra High Frequency (UHF) Range are usually the most common.