Amazon Prime

With the code, they want you to create a link between the device and an Amazon account.

https://www.amazon.com/gp/video/splash/device_linking

1. Open the Prime Video app on your device. Download it from the tvOS App Store, if haven’t already done so.
2. Select "Register on the Prime website."
3. Your registration code appears on the left of the screen.
4. Enter the code on the website.

Here are the steps from Amazon

1. Download the Prime Video app. 

2. Open the Prime Video app. 

3. Register your device—here are two ways: 

(1) Select “Sign in and start watching” and enter your Amazon account information. 

(2) Choose “Register on the Amazon website” to get a 5–6 character code, then sign in to your Amazon account and enter your code. 

Sign in to your Amazon account and enter your code 

What model of Apple TV do you have?

Are you an amazon Prime member? You need to be to access content

follow the instructions to get the code

or is this Apple ID asking to put in a two factor authentication code?