Popular Media article - these are articles from sources that are not peer reviewed and are written primarily for general information, news, or entertainment purposes. They often do not have sources, are much shorter, are not peer reviewed, and usually written by freelance writers in general language easy to understand by all. Think Popular Science, Time Magazine, Newsweek, etc.
Secondary Review Article - these articles summarize findings from other studies. The authors of these articles did not conduct the research themselves. They are discussing the research. Don't include "methods" or "results" sections. These article might include statements like, "Previous studies found..." or "A review of the literature finds...."
Primary Research Article - these articles have authors who report on their own research. They have methods and results sections. They use statements like, "I found..." or "We investigated..." They often include data.