The screen on my iPhone 7 has no color on the black gray and white
I've taken it back to the store I bought it at they couldn't figure it out anyone have any idea of a trick to Try,brand new phone
Sorry, not sure what your title sentence means, but if you are saying that the device is only showing black & white, then go to Settings>General>Accessibility>Display Accomodations>Color Filters, and turn Color Filters OFF.
If that is not what is causing it, then take it back to the store and have them give you a new device. Yours is under warranty for a year.
Cheers,
GB