POLAROID: Trying to figure out the difference between the camera that use 600 only and the one that uses Fuji?

I want to get a polaroid. I know they will stop making films eventually but I do not care. I looked online and two kind of polaroid came up. The one that uses the 600 only and the one that uses the 600 and the Fuji ones. Can anyone explain to me the difference, and also tell me if, the polaroid that uses the Fuji films too, if it's 1 film at the time or I can load a few like the 600 ones. Thank you