Romans 5:14, “(w/ v. 12-13; Just as through one man sin entered into the world and through sin, death, and thus death passed to all men, because all sinned. For until the law sin was in the world, but sin is not imputed when there is no law.) But death reigned from Adam until Moses even on those who did not sin in the likeness of Adam’s transgression, who is a type of the coming one.”
Adam is a type or form of Christ in that his action had a tremendous effect on the rest of humanity. This effect is really the point of these three verses. Paul argues that because of that first sin, all others have been affected and have died. This is all leading to the contrast between Adam and Christ, who act of righteousness provided a way for all humans to be restored.