Hello and welcome @Dannyh0198 
You should be able to leave a review for any product that has a live product page. 
There’s an issue with Firefox and Duckduckgo browsers where the review section of the product page doesn’t show up, but you can enable tracking in your browser settings and that should sort it (or swop browsers).
And here’s The Great Big Review and Testing Guide if you haven’t had a flick through that yet.