If you are using the built-in Commerce Reviews, review reports provide information about product reviews by customer and by product.
The Customer Reviews Report provides a list of all customers who have submitted product reviews. The report includes the number of reviews submitted by each customer, and a link to the list of reviews.
On the Admin sidebar, go to Reports > Reviews > By Customers.
The Product Reviews Report lists all products that have been reviewed by customers. The report includes the number of reviews and average rating, the product was last reviewed, and a link to the list of reviews for each product.
On the Admin sidebar, go to Reports > Reviews > By Products.