Call the iPhone from another phone. If it rings or vibrates, it has power. Try a force restart for your model. If the display stays black while the phone still responds, ask Apple Support to check it. If there is no response after restarting, try a working wall charger.
01Use the right force restart buttons
Section linkOn iPhone 8 or later, including iPhone SE (2nd generation or later), tap and release volume up, then tap and release volume down. Hold the side button until the Apple logo appears. On iPhone 7 or 7 Plus, hold the side and volume down buttons together until the logo appears. On iPhone 6s or earlier or iPhone SE (1st generation), hold Home and the side or top button together until the logo appears.
02If there is still no response
Section linkConnect a cable and wall charger that work with another compatible device. Leave the iPhone charging for one hour, then try the same restart again. A missed call without a ring is inconclusive because the phone could be silenced or out of coverage. If the iPhone still shows no signs of power, ask Apple Support about service.
03If the screen comes back or the phone still rings
Section linkIf the screen works again, unlock the phone and make a backup while you can. If calls still ring but the screen stays blank, tell support the phone responds with a black display even after a force restart. Ask for a diagnosis before choosing Restore on a computer, which erases the iPhone.