Arts are created by conversing with the mana in the air to infuse memories of something (a skill, weapon moves, fighting movements) an individual or various individuals have performed into scrolls.
When another person touches said scroll, the information and memories about how to use whatever was stored in the scroll become that person's own, almost like it had always been in their brains from the beginning
There are three types of arts in this world namely skill arts, combat arts and weapon arts. Weapon arts and skill arts are the most used. Combat art is the least used.
Combat art basically refers to the movements of the body and how it's used as a weapon to fight. Basically, it's like martial arts (kinda like Taijutsu from Naruto). Although combat arts function as a way to defend and protect yourself in the absence of weapons, it actually has no major way to give you enlightenment like weapon arts do.
Weapon arts are the most used arts after skill arts. They are usually of three grades; Common, Rare and Epic. Common weapon arts only have one form, rare weapon arts have two forms while epic weapon arts have three forms. Only one type of weapon art can be learnt by an individual, which is why rankers are always wary about making a decision they would stick to for life.
This was also another reason while combat arts were not given as much attention as weapon arts. They had no forms at all.
Skill arts are mostly used for mundane things like singing, calligraphy, parkour, marksmanship e.t.c. Although it may seem out of place in this super-powered world, it was a godsend for people who had no magical abilities and wanted to live normal lives and make a living. Besides, not every ranker was interested in joining guilds or the Tower so having skills here and there that could make them earn without having to depend on dangerous jobs like previously stated was really a godsend.
That being said, all arts require continuous practice and extensive usage of it to be able to fully master and grasp its usage.