There are several ways to insert a review to a page or a post on your site.
Possible ways to add a review to a page/post for the following review types:
Simple review, Product review and Social comments
1. Select the Page/Post you wish, click "Insert Review" button, it will add the review shortcode.
1. Select the posts by category, right from the Post review options - "Select post category to show current review"
2. Go to the Post you need to show the review on, "Select review" from the select box on the bottom.
1. Select the products with the categories to show the review, right from the WooCommerce review options - "Show review on products with selected categories"
You can also select the products separately, with "Show review on selected products" option in the WooCommerce review options
These were the most preferable ways of adding a review to your site, but you can also do the following:
From the "All reviews" section, copy the shortcode of the review you wish, then paste it in the Page/Post you wish, manually.