Lots of good advice for you here.
I agree with most of it.
Not all horses need shoes, depends on what kind of ground they're on, how they're ridden, what their feet are like. We have one mutt who is part mustang who has never been shod, gets a natural trim every 6 to 12 weeks, he kind of trims himself because their paddock is pretty rocky. We have shown him in 4H in western, English, jumping, trail. We've had him on all day rides over rocky trails, and he never has a problem.
Our quarter horse filly is tender footed and wimpy, so she gets natural balance shoes in the summer, and we use boa boots on her in the winter if we ride her, when she doesn't have shoes. Regular trimming is necessary though, either way, so get yourself a good farrier who you can trust, who communicates well with your veterinarian, and who is flexible in assessing a horse's needs. You don't want a farrier who worships the pasture cut and shoes for everyone, or someone who worships the mustang trim for everyone. It will all vary with the horse, the terrain, and the use.
And definitely consult a vet for these guys to get a check up. If they haven't been fed grain where they were, and you start feeding them buckets of grain they can founder, or get colic. You also need to know what vitamin supplements they may need if they don't have adequate pasture and need to live on hay. The vet will know the nutrition issues that are more common to your area.
Horse keeping is pretty complicated, and not cheap, but they are wonderful animals that will reward your efforts. Do get professional help though. Your vet and your farrier will be your best friends!