The Burner app is a popular iOS and Android app that lets you create temporary, disposable phone numbers for calling, texting, and picture messaging. It routes calls through your cellular network or Wi-Fi to keep your real phone number completely private.
Not for 2FA: Like many VoIP-based services, Burner numbers are generally not supported for verifying accounts with SMS-based Two-Factor Authentication (2FA).
Not Completely Anonymous: While the person you are calling won't see your real number, Ad Hoc Labs (the creators) keep a record of your real number tied to your account and comply with valid law enforcement requests.
It seems like an option for many uses, but as stated, you can't use it for authentication. I'm not sure if that would work with Amazon, since they send me an authentication code.