Peer reviewed journals are academic research journals which contain articles in which an editorial committee has reviewed articles for submission without knowing the authors (blind review).
To confirm that a journal is peer reviewed look for submission and acceptance dates for an article, or at the cover info of the journal to determine the presence of an editorial board or committee.
Many databases provide the option to limit to scholarly /academic/ peer reviewed journals during the search process.
Scholarly articles are not found in newspapers or popular magazines. If your topic is current there may be few.
Academic/scholarly journals can also be recognized by other characteristics: