The summoned steed could take any form, but most commonly it would take on the common forms of steeds (warhorse, camel, or mastiff, for example). However, the spirit would have to be chosen from one of three types: celestial, fey, or fiend. The steed was loyal and would act in union with the caster, and commonly had a higher intelligence than a creature of the normal kind.
If the spirit was within a mile of the caster, then they could communicate telepathically. If the steed "died" it would leave nothing behind but using the spell again would summon the same mount fully healed. Only one mount could be bound with this spell. While riding the mount, spells cast by the paladin that were normally "self only" could also encompass the steed.
The spell required verbal and somatic components.