the Supreme God form would be a form acquired with the supreme kaioshin (a new trainer), when having ultimate at max level. in appearance, Supreme god form have gray/white hairs, dark gray eyes and no particular aura. it have an enormous defense, and a great boost in other stats.
if you have a bad karma and have supreme god form at lvl 2, you unlock the corrupted supreme god form. your right arm and right face side become purple and buffed.but if your karma is good, you unlock the ultimate god form (non canon). you get a really shiny aura, a brighter hair and eye color, and a light barrier. there is no stat change between the two, it’s just like ssjb/ssjr