Removing a device
I have given my old iPhone away to a friend. I cleared it all but it’s saying I need to remove the device from my account. I don’t know how to do that. The phone doesn’t show up on my list of devices
These were the steps you had to perform on that device:--> What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support
Regards
Giulio