Overview

Skins are cosmetic changes for most abilities. Skins may alter aspects of your ability. Here's a list of what could be changed:

The model and the textures used for the model
Effects (particles and other effects e.g. sword slashes)
Idle (the idle pose) for the stand and/or the user
Pose music or/and the pose itself
Animations
Voicelines
Quotes

Skins do not alter the actual moveset nor any features of it (such as cooldowns). You can buy skins from the in-menu shop with the use of Universal Shards (u̶S), which you can obtain 400u̶S every day by doing the daily quest given by the Daily Quest (NPC). You can alternatively buy skins for less with Universal Points(u̶P), which are bought with Robux. The shop only has 6 skins on sale but it renews every day at 00:00 UTC (although you are told when exactly the refresh is in game). If you don't want any of the skins in the shop you can also buy crates for 2000u̶S or 200u̶P. Mythical and Event skins will never be obtainable in the shop. Crates will give you a skin from the skin list with a different percent chance of getting a skin from each tier (you can check the probabilities directly there, on a button next to the purchase crate option). To equip a skin go in your menu and click the Skin button, then scroll down to the ability with a skin and select the skin. You can also get event, limited or mythical skin off the limited shop. Similarly to the regular shop, the skins rotate out at 00:00 UTC, a mythical skin costs 6 uf and a event skin costs 3 uf. Limited skins can be obtained through limited crates or when they go in stock. The price for limited crates is 20 uf, and the price for every limited skins varies bewteen releases.

Here is what happens if you equip a skin for the ability that you're currently using: