Peer review is an editorial process in which an academic paper or article is reviewed and approved by experts in the same subject area.
Scholarly journals contain articles that are authored by academics for an academic audience. Articles in scholarly journals usually go through the peer review process.
In most library databases, you can choose to search for peer reviewed articles by checking a box. Here are three examples:
ProQuest Databases (like ABI/Inform, Healthcare Administration, ProQuest Central, Criminal Justice):

LibSearch - this is how you limit it once you get the first list of results; check the Scholarly & Peer-Reviwed box on the left-hand side:

Ebsco Databases (like Academic Search Premier, CINAHL, ERIC):

To find more information on peer-reviewed/scholarly articles please check this LibGuide.
For more information on the peer review process, watch the Berkeley video below to see how to restrict your search to Scholarly, Academic, Peer-reviewed articles.
If you need more help finding peer reviewed articles, contact a librarian on Chat or at your campus library.