Enchantments are a special type of skills only usable by your main character. They can be activated at any moment during battle, regardless of whose turn it is.
The only limitation is the cooldown, i.e. number of turns that needs to pass before a particular enchantment will be available for repeated use. Cooldown duration is different for each skill. Both yours and the opponent's moves are counted.
In total, the game features 16 types of Enchantments, which are divided into combat and support groups.
New Enchantments must be unlocked first and afterwards they can be improved for improved efficiency. The list of materials needed for the next upgrade can be found under the “Enchantments” tab. Enchantment parts can be found in special chests, purchased from the in-game store, obtained in dungeons or by completing main storyline quests.