You can enable Hands-free listening with Alexa in the Amazon Music app Settings.
Tap the More Options menu (three vertical dots) in the upper right corner.
Toggle on Hands-free listening with Alexa.
Keep in mind, Alexa only works when the Amazon Music app is open, in the foreground (in use), with the device unlocked. To prevent you from needing to unlock the device while driving, when plugged in to a power source or when hands-free mobile listening is enabled, the device’s screen is kept awake.
If you do not have this option in your app, then please delete and reinstall the latest build of Amazon Music, then tap the Alexa button on the bottom right. Follow the prompts to enable microphone access.
Unfortunately there are no free hands on my settings.Then I deleted and reinstalled the application, with the same results.I even logged in with another user to see if it's my account, again not Alexa in the app.
I'm sorry that troubleshooting didn't work. I've got one more thing for you to check. Alexa in the Amazon Music app is available for iOS 10 and above - so please make sure your device is updated accordingly.
I really hope that takes care of things for you. If it doesn't, I think we need to take a closer look at the details of your device and app so I'll ask you to reach out directly to our Amazon Music team through the link below.