Every time you use information not original to you, you must include an in-text citation, which in MLA style usually looks like the author's last name with a page number, e.g. (Smith 11). [See more variations of in-text citations]
In-text citations usually use the author's last name because that's what comes first in your Works Cited citation: this is the most efficient way for your reader to connect that attribution with the full details of the source.
If there's no author, your citation is going to start with the title of the article, which is what you'll use for your parenthetical citation. You don't need to use the whole thing -- just enough to be unique, e.g. ("Child Abuse Prevention").
Paraphrasing is almost always the better choice for adding information into your paper. When you paraphrase, you're able to include your own spin on the cited material, expressing and arguing your own thoughts.
Direct quotes, on the other hand, are just a rehash of what someone else has said. The shorter your paper is, the fewer direct quotes you should use!
Don't drop standalone quotes into your paper: you should always be using your own words to introduce or finish off the quoted portion (or both.) For example,
Use just what you need to back up a point and no more.