The history of The Residents officially begins in 1974. Or 1972. Or even earlier. You know what? The question of when doesn't matter.
The Residents used to be based in San Francisco, but are originally from Louisiana. Or Texas. Or... you know what? The question of where doesn't matter either.
The Residents produce music. And film. And performance. And computer software. And... you know what? I'm sensing that what cannot be pinned down either. It's pretty much whatever they're interested in at the time.
And who are they? Well that's the tricky bit. A core concept of The Residents is anonymity, so to give out names undermines the concept. Knowing that Superman is also known as Clark Kent does not explain the hero. Therefore, and you're already ahead of me here, the question of who is not important, either.
That leaves us with the most important question: why? Why do The Residents exist? The Residents began because, at the time, the world didn't have them. They were unlike who they saw already present in the art world. What they wanted to see was not available, so they made it. They did it wherever they could, and as often as possible.