what is the best way to do a communication system with two arduinos

i'm doing a project and i have to send an information of a sensor that is connected with an arduino to another arduino.

Wire works.

How far apart are the Arduinos, and how are they each powered?

Wired or wireless? What are the Arduino boards?

For wired, Serial is one way to communicate between boards. For wireless, I would use NRF243 radios. Here is a great tutorial for getting started with them.

Read the how to use this forum-please read sticky to get some good advice on what we need to know to be able to help you (see #11).