I can’t find where I am supposed to enter the 4 digit code?

Your iPhone should be paired to the Apple TV for such use.

Identify your Apple TV model - Apple Support

Depending on your model Apple TV, you should copy the code from the TV screen to your phone, or copy the code from your phone to your Apple TV.

Hello,

I am having a difficult time understanding your question. Could you please restate your question while providing as much detail as you can?

Writing an effective Apple Support Community post