Apparently lots of people have this problem and the 'apple' solution is to reset the home screen layout to factory defaults. I have no idea how this problem happened on my iPhone. I didn't do it intentionally and this is the only time it's occurred in many years of using the iPhone. I can only guess some sort of accidental triggering event but whatever caused it the icon is gone. No offense to those who like the reset solution but my home screen will take a few hours to restore to the customization so its not a great solution, particularly to a problem that can apparently be triggered by chance home screen touches. Apple - you have to do better on this one. Please provide a way to get the icon back which does not require a reset of the home screen layout to factory defaults. Thanks.
The Phone icon can not be removed from the device.
You accidentally put it into a folder.
Use Siri to find it.
ah yes, I should have pre-empted that suggestion :). It's for sure there and search finds it but then what? No folder is given in the search and manually looking in all the nested icons on all screens doesn't find it. AFAIK It's not actually in any folder that is accessible but its in some space that is hidden / protected. btw, I can execute the function from the search/find path then clicking on the phone icon but that is annoying compared to the one click from the home screen. Now maybe there is something I'm missing but many others must be too since this is a common problem (google it and see for yourself) and no one is suggesting that search helps in any way other than proving the phone icon is there somewhere. No help restoring the icon to the home screen down that path except for resetting the home screen to factory default layout. Thanks though...