It looks, at first blush, rather as though you're asking if there is an established magical system worked out by some industry group--"The Fantasy Magic Use Consortium" or something--which you must follow when writing your own, original work.

I can think of two ways I might answer this question yes.

In the first case, you should have capitalized "elementals" and probably thrown in the name of the original author or series creator. For instance, if I wanted to write a Star Wars or Animorphs novel (which I don't, but if I did), I would need to follow a lot of guidelines as to what can happen and how everything is supposed to work. So if it should have been "Elementals, like in Gimbooker Gabley's Ick! series," then the answer is yes, you must follow the rules laid down by whoever controls the intellectual property rights to "Elementals, like in Gimbooker Gabley's Ick! series."

On the other hand, if you mean that there are definite rules to creating a fantasy story that intelligent people can read, then yes, there are "rules" of a sort. For instance, the magic use should have realistic consequences. For example, if people that can summon hurricanes and tornadoes are pretty common, then are there still armies in your world? Same thing for people that can make water spring up out of the ground, why would anyone come up with the idea of aquaducts in that case? How does it affect your preindustrial society to have people who can blow up a city running around? Does anyone even bother with building stuff if a quarter of the population can demolish any grounded structure?

These sorts of questions generally are answered by using a system of costs and limitations on magic use. The classic limitation is that only a select minority can really do much with magic...variations abound but relative scarcity is quite important in dramatic economy generally. We tell stories about the exceptions, after all, not the rule. There isn't one established cost, but generally it is believed that the cost should be enough to offset the benefit of using magic in most cases, so magic is usually a last resort. I like costless systems myself, because I find the questions raised by unlimited magic use far more interesting than the fairly tired themes that infest most fantasy.

That's why I'm on the Speculative Fiction side of things myself. The whole point is "what if?"

Your book, your world, your magic.

Do what you want.

The nice thing about writing Fantasy is, there aren't any hard-fast rules like Sci-Fi, so almost anything goes. It just takes creative originality.