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.
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.