>>>If you are going with FBA then Amazon don’t share your details with customers so for customer review you can send email to them. But Amazon provide you encrypted email id in order detailed page. If you have FBM, in that case, you can contact your customers by calling to them.
For customer review after delivering product ask them to go to orders tab > then Your orders option. In your orders , he/she will see the details of all the order requested, in that area, there is option of product review.
here is the screenshot: