hello!today your gonna spawn a "super horse" or named PowerfulHorseSky,then now there are 6 steps,follow it,enjoy!
Steps:
1.start with a world (flat or any).
2.get command block using this command:
/give (username) command_block
3.copy the command,then paste it on your command block.
4.then activate it.
5.before riding the horse get diamond,gold, or iron horse armor and saddle.
6.then ride in the horse,click "E" then put the horse armor and saddle on it.
if it have problem dont do it again,your minecraft world with get stop.
Thank you!!