When you need an interpreter by your side, on-site interpreting is the best option. On-site interpreting is the traditional form of interpreting.
With telephone interpreting, the person using an interpreter and the client are in the same room but the interpreter provides interpreting over the phone.
Video interpreting is like telephone interpreting with the user and client in the same room but with the interpreter working via a video link rather than on the phone.
Simultaneous interpreting at conferences involves the interpreter speaking while the speaker talks, with a 3-5 second delay.
The interpreter will accompany you to your meeting and interpret, e.g. at a business negotiation. The interpreter will interpret a few sentences at a time.