This page explains what a peer-reviewed journal is and how to find them in databases.
Most databases allow you to limit your search to just peer-reviewed articles, as in the example below from an EBSCO database. You just click on the check box in front of Scholarly (Peer-Reviewed) Journals.
Here is how you limit your search results to Peer-Reviewed Journals in Gale journal databases on the results page. Just click on the check box in front of Peer-Reviewed Journals, as is shown below.