Enchanter's magic (which is distinct from witchcraft, wizardry, magician's magic, and sorcery) is one of the most powerful types of magic: where a witch might require complex ingredients and much chanting of spells, an enchanter might simply wish and the thing is done - or not, depending on the difficulty of the task and the enchanter's power.
Abilities that are typical of enchanter's magic include the ability to conjure and banish fire, to teleport things from place to place, to make things invisible, and to see the invisible through witch-sight.
Enchanters can be more or less powerful (although there do not seem to be any weak enchanters), and some of the most powerful have more than one life. (Perhaps more correctly, the ones with more than one life are the most powerful.) The most powerful of all are the nine-lifed enchanters.
No enchantresses have yet appeared in the Chrestomanci series.
Hearsay: Diana Wynne Jones has mentioned that female enchanters exist, but none has yet been chosen to be Chrestomanci.