Follow these steps:
1. Open your Speechify App
Open the Speechify app on your Android device, tap the + button at the bottom-right of the screen.
2. Open the Accessibility Browser
From the Import menu, scroll down to the Accessibility Browser section.
Tap Accessibility Browser to expand the options.
3. Log in to Amazon
Under Accessibility Browser, select read.amazon.com.
Log in using your Amazon/Kindle account credentials.
Once you are logged in, you can access your Kindle content through the browser and use Speechify to read it aloud.
Troubleshooting
If your Kindle book does not load or Speechify does not start reading, make sure you are logged in to the correct Amazon account and try reopening the Accessibility Browser.