Tap to launch Settings from the SpringBoard.
Select General from the Settings menu.
Choose Passcode & Fingerprint from the General menu.
If you do not already have a lockscreen passcode set up, tap Turn Passcode On.
Input a new passcode and re-enter it when prompted.
Choose Fingerprints from the Passcode & Fingerprints menu.
Select Add a fingerprint... from the Fingerprints menu.
You will be prompted to set up a fingerprint.
Place the finger you use to unlock your iPhone onto the home button until the device vibrates then lift up. Repeat this process until the gray fingerprint displayed is fully red.
You will then be prompted to capture the edges of your fingerprint. Repeat the same process of touching your finger to the sensor then lifting up but this time focus on capturing the sides of your fingerprint.
Once enough data has been captured your Touch ID will be ready for use. Tap the Continue button.
You will be returned to the Fingerprints menu. Here you can register another fingerprint or enable your fingerprint for use when purchasing apps and media from the App Store and iTunes Store.
To enable iTunes & App Store use, simply tap the appropriate switch in the Fingerprints menu. Note: This switch is disabled if you aren't already logged into the App Store.
You will be asked to confirm your Apple ID password. Enter your password and press the OK button.
You will now be able to use your fingerprint to confirm iTunes & App Store purchases.
To test out fingerprint authentication, lock your device using the Sleep/Wake button. Then press the button again to wake the device. You'll notice a slide to unlock message at the bottom of the lockscreen.
Instead of sliding to unlock and entering your passcode, simply place your registered finger on the Home button, holding it still momentarily. The iPhone will detect your finger and if it matches a registered fingerprint it will unlock the device and take you straight to the SpringBoard, without needing to input your passcode. If the iPhone is unable to authenticate the fingerprint a try again message will be displayed at the bottom of the lockscreen.
Making purchases from the App Store using your fingerprint is a similar process.
Tap to launch the App Store from your Springboard. You may be asked if you would like to use your fingerprint for purchases. Tap the OK button.
Enter your passcode to authorize fingerprint purchases and tap the OK button.
The next time you attempt to purchase an app, you'll have the option to scan your fingerprint instead of entering your login information.
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