What is the difference between the rules of Martial Arts & Mixed Martial Arts?

Mixed martial arts is a sport that has rules and takes techniques that fit in those rules from different martial arts styles. Since it tries to accommodate many styles more things are allowed to score.

Traditional martial arts are whole systems intended for self defense. There are also sports versions of the different styles which take the traditional arts, exclude the lethal techniques and put the focus on scoring rather than maiming or killing an opponent. It also limits what you can score with. If you have a 'stand-up' style kicks and punches score, never mind that these styles in reality also include take downs which for the sake of the sport has been removed. If you have grappling/throwing styles then your throws and submissions score.

Different tournament circuits have different rules so it is always a good idea to familiarize yourself with the rules.

There are thousands of different martial arts styles. There is no set of rules that are used by all of them. Mixed martial arts is commonly used in sport competition and there are rules.

mixed martial arts doesnt have any rules because its not a competition. the ufc has rules mma is just a word to describe the fighting style used.