There are mainly two kinds of interpreters: Simultaneous interpreters and Consecutive interpreters. The kind of interpreter needed depends on the scale and nature of your event.
Simultaneous interpreters work in pair per language and sit inside a booth to verbally translate what is being said through a microphone to listeners. Simultaneous interpreters are usually used at conferences and large meetings which require real-time interpreting.
Consecutive interpreters listen to a segment of speech and translate the speech consecutively after the speaker has finished each segment of his/her speech. Consecutive interpreters are usually used for business meetings and discussions.