Are you asking about making identical duplicates of notes?
Or about adding identical duplicate card types/templates for a certain note type?
While there can be some reasons to do either one, they are both probably bad ideas to do very much of, because you would be duplicating your workload [see link]. If you have a need to duplicate one note at a time – Notes > Create Copy.
Or maybe if you say more about your ultimate goal, someone might be able to suggest a better way to get there.