How can you create horses on HorseIsle?

It depends on what game you are playing.

HorseIsle 1

On this game you must buy a Pawneer Order from the shop, they cost $8 USD (real money). If you can't pay with real money you can try buying one in game for a large sum of game money! To get here, click to go to the server you wish to buy the Pawneer Order on, then select to purchase a Pawneer Order on the list of items to buy. Then you can go to the Pawneer and order your horse there!

HorseIsle 2

On HI2, you have to buy a Horse Token from the Shop page, where they cost $8 USD. Like on HI1 you can buy them from other players for good sums of game money. Then you can order the horse from Inventory > Game Tokens > "USE" Horse Token.