Hey there!
The voyagers were space probes launhced by NASA to explore the universe farther than we've ever seen. They've travelled millions of miles, and have given us amazing photos and information - including the amazingly famous "pale blue dot" - taken in February of 1990.
Voyager 1 was launched on September 5th, 1977, and Voyager 2 was launched August 20th, 1977.
Voyager one has travelled the farthest, and is currently in Interstellar Space, beyond the far reaches of the solar system. On the other hand, Voyager 2 still remains in the Heliosheath - where there's an abundance of solar wind and gases.
Hope this helps!