Note that you can set up a free Kobo account, and then post reviews to books even if you haven’t bought them! (And you can buy and read from Kobo via any device with their app.)
- Go to kobo.com
- Sign in to your account (or create an account if you don’t already have one)
- Search for the book you want.
- Click on it.
- Scroll down until you get to the Ratings and Book Reviews section.
- On the right is a white and red button “Share Your Thoughts”.
Note: I love the wording of “share your thoughts” instead of “write a review”. It’s much more personal and, I think, gives the person writing a bit more free reign mentally.