Moving with horses is very, very different from moving with a dog or cat. You must prepare months in advance and coordinate with several people to ensure that you and your horse will arrive in your new home perfectly safe, happy, and healthy.
Talk to your veterinarian about vaccinations, tests, and other health requirements for a long-distance move. For your peace of mind, consider purchasing equine insurance to cover your expenses in case something untoward happens during transport.
Weeks before the move, train your horse to enter and exit a trailer without getting spooked. Introduce leg guards that will keep it upright and stable throughout the long ride.