I used to train horses growling up. Historically they were used for warfare and farming and transportation
Is horse training hard?
Yes it is depending on the individual horse. There is a tremendous amount of controversy over various training techniques.  
O really can you name a few?
I don't remember specific names off the top of my head. A lot of methods are usually referred to by the famous trainers name. The only term I remember that isnt someone name is "gentling."
Do you train them for cops?
No, I only trained our personal horses for typical equestrian activities like barrel racing and trail riding.