You've attuned your mind and body to the base aspects of the world. The elements of Fire, Water, Lightning, and Wind are all at your disposal. With their assistance you are able to manifest them into their raw physical form, augmenting your Monk Weapon and or Unarmed Strikes to the respective element.

Monks of this tradition often tattoo crests or symbols representing element on their body. These may vary from monk to monk or monastery to monastery as harmony with the elements is a reflection of the self and how the elements reside within.

Note: any reference to monk weapon includes unarmed attacks

Way of the Four Elements: At 3rd level you gain the ability to channel the elements into your attacks. The raging fists of fire, the swift strikes of lightning, the flowing whips of water, and the whiplash of the winds.

Enchanting with Element: You coat your monk weapon in a chosen element, augmenting all attacks to have the properties of that element. This will cause augmented attacks to be treated as magical, as well as have the associated element. 

This Way of the Four Elements uses a resource called Element. To initially augment  your monk weapon you first spend a point of element as a bonus action, then you can select an element to empower your monk weapon with. It lasts until the start of your next turn (one minute out of combat), however it can be extended if you attack or are attacked. If you don't attack or are not attacked, you will lose your elemental enhancement

You are able to swap elements as a bonus action after spending a ki point or an Element. The number of Element you have follows the same as the barbarian’s rage count, and can only be regained on a long rest.

(attack that are not augmented will not be treated as magical until 6th level’s ki empowered strikes)

For the sake of Water and Wind: Water is to be treated as ice damage but can be flavored as water or ice wrapping around your monk weapon. Wind is to be treated as thunder damage and can be flavored as gusts of wind billowing through your monk weapon or as a booming sound coming from your attack when it strikes. Fire and lightning are treated normally as their respective element.

Element Enhancements: Starting at 6th level, your affinity for the elements grows stronger. You can spend your bonus action and a ki point when augmented with the associated element to gain one of the following benefits:

• Fire: your flames burn twice as hot, add an extra damage die to your damage roll for the next attack.(this die is counted for critical hits)
• Water: you’ve learned to use your empowered water to redirect attacks, roll a dice equivalent to your martial art’s damage die and remove it from an attack roll made against you. (use your reaction and a ki instead of a bonus action)
•  Wind: You’ve mastered being swift and silent like the wind, for the next minute add an extra 5 ft to your movement and gain advantage on your next stealth check.
• Lightning: you strike swift and true, following an attack action you may make three extra attacks.

Elemental resistance: Starting at 11th level, you gain resistance and vulnerability to the following when augmented with the associated element.  

• Fire: resistance to fire and burning effects, vulnerability to ice / water
• Water: resistance to ice/water/acid, vulnerable to lightning
• Wind: resistant to thunder and knockback effects, vulnerable to fire
• Lightning: resistant to lightning and paralysis, vulnerable to thunder and knockback effects launch twice as far

Elemental Affinity: Starting at 17th level, you can unleash a devastating attack on an enemy, using your action, bonus action, and reaction you are able to shift between all the elements (starting and ending on whichever you choose) to make powerful attacks. Each of your strikes negate elemental resistance/immunity, and also deals an extra damage dice of the element’s damage (resistance/immunity applies to this damage).