how to reboot and restore my iphone6s
cannot turn on my iphone even it has power connected
iPhone 6s Plus, iOS 14
Question marked as
First, try a forced restart.
• Press and quickly release the volume up button
• Press and quickly release the volume down button
• Press and hold the side button.
• When the Apple logo appears, release the button.
Force restart iPhone - Apple Support (IN)
If that doesn't work, make an appointment at the Genius Bar to have it diagnosed.
Genius Bar Reservation and Apple Support Options - Apple