In the original games, Ho-Oh's most notable move, was Sacred Fire.
Today, it is still Ho-Oh's signature move, but it's not as popular as before, due to the fact that the release of event Pokemon with signature moves have increased.
Only Giratina can learn shadow force. The only thing that proves or said that Giratina can learn the move is because it is it's signature move.....
It can only learn it as a egg move.
only jirachi can learn it
Graveler can learn the move Dig but not naturally. Graveler can only learn Dig from a TM or was bred to know the move.
The only move that it can learn is transform.
No it can not learn this move because only Ditto can use it.
Most Pokemon can learn that move think of it this way Pokemon that have hands can learn it some Pokemon learn it from the move tutors however some can learn it via egg move only.
Then that Pokemon cannot learn it. Only starter Pokemon can learn the ultimate move. No other Pokemon can learn them.
Pikachu
Shut up and listen WHAT the hell is hooh hooh or Ho-Oh is a legendary Pokemon in the Pokemon games Pokemon Gold/Silver/Crystal. I don`t exually have an answer for the first question though...
JIRACHI and only jirachi can learn it because only physic and steel together can make this move
Smeargle is the Pokemon that can learn sketch, and its its only move