Enchantments are upgrades that can be equipped to weapons and armor. Applying enchantments on items requires enchantment points which can be obtained by leveling up your character. To use an enchantment, go to the inventory menu and select an item to view their enchantments. The possible enchantments that can be placed on an item are random from item to item. Thus, two of the same items could be very different because of the enchantments they have.
There are multiple different types of enchantments, each having a special effect. All enchantments have 3 tiers. Each tier increases the strength of the enchantment but cost an increased amount of enchantment points to upgrade.
Salvaging an item will give you emeralds and all the enchantment points that you spent on it. So feel free to try out different weapons/armor and enchantments as you play!