1) The go-to magic for giving general powers is Transformation/Disruption. Take someone out with it and declare the takeout result to be an alteration of their nature. Add more power to the spell for duration and/or resistance to dispelling. Doing it to an item and declaring the item gives powers to whoever uses it is basically the same thing, with only minor changes. Making an item be an artifact merely requires you add Physical Immunity on top of whatever other powers you give it so it becomes indestructible.
2) Yes, it's THAT easy to give someone powers. Just take them out and transform them or give them an item. A magical pact, a bit of soul-stitching, a strong enough curse. Hell, even an inexperienced Harry Dresden in Fool Moon was pretty sure he could manage those magical belts. BUT, that kind of thing has costs beyond the magic for it;
3) Granting someone powers has a cost - either through an item or through direct alteration, they must spend Refresh on them. If someone picks up a magic item or is altered into something they don't have enough refresh for, tough luck; they become NPCs as their refresh goes to the negatives. That's exactly what happened to MacFinn when that curse turned him into a Loup Garou or those FBI agents when the belts turned them into werewolves.
4) Altering someone's nature directly, especially against their will, bears an additional cost; it breaks the 2nd Law of Magic: You Shall Not Transform Another.
To sum up, giving someone powers or making magic items is easy but costly.