The camera gets its name from the 6x6 frame size. That means it's a square format photo. You get 12 photos per roll (13 if youre lucky).
Square format is a classic format for film photos. It's been used for generations. I like the way your eye gets caught looping around a frame, as there isn't a tall or wide side to it.
The "MF" in the "Mamiya 6 MF" means "Multi-Format". That means there are also special inserts to add, allowing you to shoot other formats too. I think the best is the 35mm adapter which let's you shoot panorama photos.
Another feature of the Mamiya 6 MF is that the lens can retract into the body, similar to an extending lens on a point and shoot camera. This makes it pack smaer and be easier for travel.
It's also one of very few medium format cameras to have a built in self timer. But that is because the shutter is controlled via a battery. So make sure you always have an extra.
My primary work as a photographer is wedding photography. I love this camera because it's easy to carry with me (it's light) and the medium format film is always so rich and detailed. It also has a working flash sync for when you need it.
Though the camera only has 3 lens options, it is a great environmental portrait camera. It shows a lot of a scene. Has just enough depth of field to separate the subject from the background and still be crisp.