You don't, its part of the backing of the device. Apple can replace it though.
You'd need a special screwdriver to unscrew the two screws on the bottom of the phone, then the back would easily slide off and you'd have access to the battery.
The iphone 4 does have a removable battery, but it is difficult to take out and not a typical cell phone battery that you can just pop in and out. It is possible to remove the battery from an iphone 4, but not an easy process. It requires you to pretty much disassemble the whole phone.
1432 mah battery
To get the serial for your iPhone you can remove the battery and you will be able to see it.
3 hours
The battery that is most suitable as an iPhone cellphone battery replacement is a genuine iPhone battery from Apple. You should not take the risk of damaging your iPhone by purchasing another type of battery.
you meen iphone 4? if so yes 2x bigger! but iphone 3GS i don't know, hope that helps!:)
The Apple iPhone 6 Plus has a better battery life than the Apple iPhone 6.
a battery
battery produces heat touch screen does not require pressure
1. Remove negative battery cable 2. remove positive battery cable 3. remove battery 4. install new battery 5.attach positive cable 6.attach negative cable
take to a iphone store
Depends how you use it. Normal use required daily charge.