Which artist invented the collage art form, and in what year? what are artists doing, or what principle are they following when they created a collage?

Georges Braque and Pablo Picasso both coined collage in the beginning of the 19th century, where the artwork is made from and assemblage of different forms this creating a new whole, it became a distinctive part of modern art

No,sadie told me she doesn't want to go said margret.

Maybe because it was so unique, a form of art, and they could easily store things in it and no one had ever done that before. i’m not sure but that’s what i think : )