Yes they can!
To submit a book review, you first must have a Bookshop account. If you have not yet purchased a book from one of our authors, you can create an account here - https://store.bookbaby.com/myaccount/login.aspx
Go to the Bookshop url (web page) where the book is purchased, and scroll down to the bottom of the page.
Just above the section that says "Review", click on the Log In link and log into your Bookshop My Account.
This opens the review section for you to enter:
A Review title
A one to five star rating
Review text - up to 3200 characters.
click Submit.
The author will receive your review and publish it after they have approved the review for their site.