So this question is a little vauge.
But I know a method on how to teach any move for Smeargle in Generation 7 (I use it myself)
When a Smeargle uses Sketch, It will learn ANY type of move, whether that be exclusive to a certain Pokemon or not. I haven't tested out if you can use a Z-Crystal for that exclusive move it learned though, but probably not.
So basically, you must find a wild Smeargle, and make it call for an ally. I think what would be best is to use an Adrenaline Orb and use false swipe or some other move. However, you must use the Pokemon you want the Smeargle to learn and you want to keep it. So, anyways, when the Smeargle calls for a new Smeargle, you are going to want to use the move you want the other Smeargle to learn on the first Smeargle. That same turn, the ally Smeargle will probably use sketch and copy the move you used on the other original Smeargle. And there you have it, the Smeargle learned it.
Sorry If this doesn't answer the question. I thought it might help.
