Power button is located at the right side of the iPhone 6s and is an essential element to turn off or turn on the phone whenever you want. The power button of iPhone also works as a sleep and wake up button when phone is powered on. The iPhone 6s has a power button assembled along with the microphone during the manufacturing time. If the button stops working it needs to be replaced with the complete power button flex assembly. If your iPhone 6s power button also faces some issues it is the time to get it replaced instantly as it is near to impossible to use iPhone 6s without the correctly functioning power button.