I believe purchasing by voice does have to be enabled initially through the app as well. https://www.amazon.com/gp/help/customer/display.html?nodeId=...
Edit: I looked in my Alexa app and there is also a voice recognition option, so you can use it to only allow purchasing via recognized voice patterns and require a PIN for anything else.
I believe purchasing by voice does have to be enabled initially through the app as well. https://www.amazon.com/gp/help/customer/display.html?nodeId=...
Edit: I looked in my Alexa app and there is also a voice recognition option, so you can use it to only allow purchasing via recognized voice patterns and require a PIN for anything else.