This problem should be eliminated immediately. Connect your smartphone to a charger or use a wireless dock. If the gadget is discharged, it will take up to 1 hour for the logo or charge level to appear on the screen.
When connecting the device to a charger, check the integrity of the wires and contact input.
If the iPhone turns off and does not respond or vibrates when you press the button, but the screen does not light up, the reason is software or hardware. If it's just an OS crash or a malfunction of one of the elements of the device, rebooting the device will help. Distinguish between normal and hard reboots. In the first case, the algorithm of actions is as follows: