You can open the skins menu in the Event Board or the Inventory.
The game has a lot of skin items received for completing events, for winning tournaments or bought for PVP trophies. You can see how each item will look individually on your character, or the entire skin as a whole with the "Preview" button. In the item description you can remove / put on the button, see its bonus and the date of the last event in which it was issued.
On the last tab, you can add or replace an existing bonus in skin items. To do this, use enchantment books received in events or bought in a PVP store.
For enchantment - you need to transfer the skin item from the character to the lower cell and the enchantment book to the upper one, after that the "Enchant" button will appear. One skin item can have only one enchantment, with the exception of the mage's staff. You can use two enchantment books on the magician’s staff.