Amazon.com/mytv is a registration portal of Amazon Prime from which members can watch thousands of movies and TV shows for free from their device some features require a premium subscription. The instant video service can only be watched after registering your device with a simple amazon activation code.
“Amazon Prime code” typically refers to the code used during the activation process when linking your Amazon Prime account to a device, such as a smart TV, streaming media player, or gaming console. This code is displayed on your TV screen when you try to activate the Amazon Prime Video app on a compatible device.