How to enable 2FA for Amazon?
Install Secure ID
Secure ID enables you to have a single mobile app for all your 2FA accounts and you can sync them across multiple devices. Install Secure ID on your device by searching for it in your device’s app store .
Locate 2FA Setting in Amazon Web app
Are you using Amazon mobile app? 
1. Login to Amazon and click Accounts and Lists.
2. Click Your Account option.
3. Now click Login And Security on Amazon page.
4. On the next page displayed click Edit button displayed with Two Step Verification Settings.
5. On the amazon webpage click Get Started button and then select Authenticator App radio button which will expand the text area for authenticator app.
6. Launch Secure ID app on your device. Click ‘+’ icon and scan the QR code displayed on amazon screen.
After scanning the QR code Amazon logo and six-digit code will be displayed on Secure ID screen.
7. On the amazon page enter the six-digit code(generated by Secure ID) in a text box displayed below QR code. After entering the code click Verify OTP and Continue button.
8. Enable/disable the checkbox Don’t require OTP on this browser according to your requirement. Click Got it. Turn on Two-Step Verification button.
Two Factor Authentication is now enabled for your App.
Congratulations! Secure ID is now ready to use for Two Factor Authentication for Amazon.