WORLD OF WARCRAFT - Can hunters use magic? help?

I see all these people with magic stuff. lol, I mean, when I click on their potrait there's always something like "increases intellect by 10 for 30 minutes". It's not a potion though, so I don't think it's from alchemy. And everyone always gives it to me. How do I do it to myself? And how do I give it to others?