Yes you can, but you need to make sure that it's relevant to what you want to say in your essay and a paraphrased quote is usually better than a direct quote. Every Uni should have some sort of assistance/fact sheets for their students on academic skills - at UNE they have a whole series of short online courses (by short I mean you do them in 5-10 minutes) to help you brush up on your writing skills. Have a look on your Uni's website and see if they offer the same thing anywhere.