My daughter's iPhone 6 Plus is broken but before it totally broke it turned on the 3G and I don't know how to turn it off so it doesn't keep costing me more $$ until it can get fixed. Thanks
If the Touch input is still working, press and hold power button for three seconds, and then swipe the phone off. You can use another device to approximate where the slider is on the screen (usually a half inch from the top of the LCD).
Otherwise, press and hold the power button and home button down for about 40 seconds, the ln hold the home button down for another 10 seconds. This boots the phone into recovery (DFU) mode. This mode is normally used to recover the phone from software issues, but will power the phone off automatically if left alone for approximately 10 minutes.
Note that if the iPhone crashed and rebooted due to a piece of hardware such as the screen failing, the phone will not connect to Wi-Fi until the device is unlocked. This is for security reasons although it is a very annoying feature in such a circumstance.