If you’re referring to the wavy pattern along the cutting edge, that’s not from the folding process. The hamon is added to the blade during the quenching process, by adding clay to the steel. The clay causes the covered steel to heat differently than the uncovered steel. That differential heating is what is visible as the hamon.

It’s largely decorative, but does have function as it determines what part of the blade can be sharpened to an edge.