Does a Paladin's steed, when not using it as a mount, attack and perform other tasks through your command, like a Ranger's animal companion?
I'm under the impression that a Paladin's steed works like an animal companion since it says in the Player's Handbook under the Find Steed spell that you "fight as a seamless unit."
Find Steed says that:
You summon a spirit that assumes the form of an unusually intelligent, strong, and loyal steed, creating a long‑lasting bond with it.
[...]
Additionally, if your steed has an Intelligence of 5 or less, its Intelligence becomes 6, and it gains the ability to understand one language of your choice that you speak.
Given that it's loyal, intelligent, and understands you, you can certainly command it. As for what it can actually do:
Appearing in an unoccupied space within range, the steed takes on a form that you choose: a warhorse, a pony, a camel, an elk, or a mastiff. (Your GM might allow other animals to be summoned as steeds.) The steed has the statistics of the chosen form, though it is a celestial, fey, or fiend (your choice) instead of its normal type.
So it can do anything that a creature of the type whose form it took can do. For example, if your steed takes the form of a warhorse, it has access to the warhorse's Hooves attack and Trampling Charge ability. Anything more than that is up to you to negotiate with your DM, although it would certainly be reasonable to expect it to, for example, pull a wagon.
Note: Jeremy Crawford, official source of rules interpretation for D&D 5e, agrees that the steed can attack independently.
Ryan Hagan: Following up on yesterday. So Find steed steed can attack on your turn? What about not mounted? Forums are abuzz.
Jeremy Crawford: While ridden, the steed follows the normal mounted combat rules (PH, 198). Unridden, it has normal action options.
"mount" and "steed" aren't interchangeable terms. "your steed serves as a mount" doesn't mean the same thing as "your steed is limited to being used as a mount."
The official half-orc paladin pregen (found, with other sheets, here: http://dnd.wizards.com/articles/features/character_sheets) comes with a brown bear with an Intelligence of 6. The sheet also lists a mastiff with an intelligence of 3.
Steeds are intelligent creatures. In 5e your steed is not "just" a warhorse. It's a fey, fiend or celestial that has manifested as a warhorse (or whatever) (you can find this in the spell description on page 240 of the Player's Handbook). Since they are intelligent creatures which can be used as mounts they follow the rules on page 198: "Intelligent creatures, such as dragons, act independently... An independent mount retains its place in the initiative order."
Thus the steed is an intelligent ally who is mystically bound to the Paladin. As such, the Paladin doesn't "give orders" to the creature, but he can communicate with it. The steed understands (per the spell) and can choose to follow the paladin's lead or not. More than likely the creature is well disposed towards the Paladin, but since this creature is a spirit it may not take kindly to the Paladin breaking his oath.
The steed DOESN'T gain the Paladin's proficiency bonus. The Paladin CAN'T give up an action to give it commands. Those abilities belong to Beastmaster Ranger characters. That doesn't mean the steed can't choose to make attacks.
I assume the mastiff pet on the pregen sheet would require a successful animal handling roll for each command it was given and probably only has a limited number of available commands.
If this seems like the Paladin is infringing on the Ranger, that MAY be partially be design (there is evidence of this in other areas, such as Hunter's Mark not requiring a spell slot for a Vengeance Paladin).
Since you provided more clarity to your question: "...I'm talking about if a Paladin's steed requires using an action to command it to attack when you are not riding it. Just like how the Ranger must forgo an action for its animal companion to attack..." I can now provide a clear answer, and that answer is
No, the caster of 'Find Steed' is not capable of forgoing an action to command the Steed to take a specific order or command.
Here's why:
I firmly believe that despite our wishes to make 'Find Steed' more than it actually is (myself included as I love the Paladin class), the spell ONLY does precisely as it states it does; and the actuality of the 'Find Steed' spell by RAW (Rules as Written) simply replaces the need to purchase a Warhorse or other mount and enlightens the creature with extra intelligence, the ability to share self targeting spells that don't effect your weapon, and the ability to understand a single language and communicate telepathically; thus fighting as a 'seamless unit.'
'Fights as a seamless unit' has no other explanation or rules attached. The inclusion of this descriptive phrase does not impart any extra abilities the mounted combat rules don't already impart, and simply reinforces the extra oomph 'Find Steed' gives to this amazing undying spirit creature as outlined above. Unlike the rules surrounding the Ranger's Animal Companion ability; 'Find Steed' does not make you or your steed special in that you gain an unwritten ability to command them by forgoing an action, or by any other means for that matter, while not mounted on it. It would be included in the text as an exception to the mounted combat rules if that were true.
Just because the spell summons a spirit that takes the form of a Warhorse with it's exact statistics and a few extraordinary abilities; its statistics do not say it's capable of taking commands/orders to do as YOU wish it to while not serving as your mount (unmounted). Just like if you went out and purchased a warhorse, you get a mount that follows the rules of mounted combat and otherwise a creature that acts on it's own whims and doesn't take commands unless serving as your mount (mounted).
There is no paragraph or sentence in the entirety of the lengthy 'Find Steed' descriptive text that would allow a non mounted Paladin to control the steed directly. You can communicate with it, telepathically even, and issue requests; but like all requests it will be up to the steed (read: DM) to decide to carry out the request.
RAW, no. The Find Steed spell is closer to the Find Familiar spell than the Ranger's class ability. But it is neither, it calls forth a mount. The spell doesn't grant the steed attacks, so we have togo by the rules for mounts:
It moves as you direct it, and it has only three action options: Dash, Disengage and Dodge ... You can either control the mount or allow it to act independently. Intelligent creatures, such as dragons, act independently.(PHB 198)
And, my answer has been confirmed by Jeremy Crawford, when someone asked him this question on Twitter:
Yair: [D]oes a paladin's mount count as intelligent for the purpose of mounted combat?
Jeremy Crawford: Find Steed summons a mount that is under the paladin's control, regardless of the mount's Intelligence.
Yair: [D]oes that mean it doesn't get to attack?
Jeremy Crawford: Correct. It follows the rules for a controlled mount.
