In general, there are three types of resources or sources of information: primary, secondary, and tertiary. It is important to understand these types and to know what type is appropriate for your coursework prior to searching for information.
It's sometimes difficult to distinguish among these three types and they do vary by discipline and subject..
Scholarly (aka academic) articles are written by and for academics, researchers, and experts in the specific topic or broader subject area of the article.
Peer reviewed (aka refereed) articles are those which have been reviewed prior to publication by other experts in the topic of the article. Often reviewers are external (not members of the journal's editorial staff or board).
Note: Not everything in a journal is peer reviewed; letters to the editor, book reviews, news items, and other short works without listed references are typically not peer reviewed the way more substantive articles are.