Here are three ways to check if your journal is peer-reviewed:
Check the journal website - "Google" the name of the journal to find the publisher's website. Look for a link that says "Information for Authors" or "Instructions for Authors." Here's an example from the British Medical Journal (BMJ).
Check Journal Search - Search for the name of the journal in Journal Search. Then, look for the icon .
Use a library database to find out - Search for the name of the journal in Journal Search. Then, click on the database link that contains your journal for a full description.