This 3 minute video describes three ways to answer this question:
Not all journals are peer reviewed. If the three techniques in the box above yield no results, try a different journal title.
It is also possible that some contents of a peer reviewed journal will not have been peer reviewed. For example, editorials may not be peer reviewed but research articles generally will be. This varies from journal to journal; look for "about the journal" or "instructions to authors" or "journal homepage" for guidance on this.