Information literacy is the ability to find and critically examine information. To do this we need to figure out which information sources are credible and which are not.
Credible sources are written by authors respected in their fields of study. Responsible, credible authors will cite their sources so that you can check the accuracy of and support for what they've written.
Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work. It functions as a form of self-regulation by qualified members of a profession within the relevant field.
In order to qualify as an academic or scholarly source, an article must go through the peer review process.