can i enchant ghostly touch on other player's creature?

[Tilo]

can I put ghostly touch on opponent's creature?

[Arix]

Sure. It won't do you much good though, since then your opponent's creature gains the ability.

[Kenji]

In case Arix didn't already make this clear: your opponent's creature will have "Whenever this creature attacks, you may tap or untap target permanent."

"You" in this context means your opponent, as it is his creature doing the attacking. Your opponent gets to tap or untap target permanent, not you.

[kartiv]

but here you said something different:
creature with enchantment gets controlled by opponent what happens to enchantment

and you even brought armadillo cloak as an example where the controller of the enchantment benefits from the enchantment not the controller of the creature?

[Kenji]

Are you reading the cards entirely and completely? Because if you did, there would be no confusion. There's a great deal of difference between the text of the two cards:

Ghostly Touch: "Enchanted creature has "Whenever this creature attacks, you may tap or untap target permanent."

Armadillo Cloak: "Enchanted creature gets +2/+2 and has trample.
Whenever enchanted creature deals damage, you gain that much life."

See the difference? Ghostly Touch specifically gives the ability to the enchanted creature. Whereas Armadillo Cloak itself is the source of the triggered ability that causes you to gain life.

In both cases, the person that cast the Aura is the one who controls it. However, with Ghostly Touch, since the enchanted creature gets the ability, it doesn't matter that you maintain control of the Aura -- if your opponent's creature is enchanted, they'll control the triggered ability of their creature.

Does that clear it up enough? I could explain it in even simpler terms, I suppose, but it's already pretty simple as-is.