where is my phone widget on home screen?

I'm not aware of a phone widget. See: Use widgets on your iPhone and iPod touch - Apple Support

If you mean the Phone app, the Phone app is not one of the apps that can be deleted but with iOS 14 it can be removed from the home screen. If you have iOS 14, go to the App Library (swipe left past your last home screen). From there you can touch and hold an app and slide it left back to the home screen.

Touch and hold down lightly until all of the apps on that screen start to jiggle and then slide it to the far left of the screen until it goes to the next screen.