How to Set Up Touch ID on an iPhone or iPad

Touch ID is a new physical feature that Apple included on the iPhone 5s, iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPad Air 2, iPad Pro, iPad Mini 3, and iPad Mini 4.[1] Touch ID saves the user's fingerprint for security and verification purposes, such as unlocking the device, making purchases on the iTunes Store and App Store, or for Apple Pay.
1.Be sure that all your fingers are clean, dry and healed. Moisture, lotions, sweat, oils, cuts, or dry skin might affect fingerprint recognition; also, activities such as exercising, showering, swimming, or cooking may also affect your fingerprint.
2.Open the Settings app and navigate to the Touch ID & Passcode section. The Settings app's icon is a grey gear and is pre-installed with every Apple iOS device. Before you enter the Touch ID & Passcode section, you may be prompted to enter an existing passcode (if applicable).
3.Choose Add a Fingerprint. Now, a new screen will open with instructions and graphics on adding your fingerprint.
4.Lift and rest your finger on the home button until the fingerprint graphic fills up. Do this as if you were normally touching the home button with that finger, but be sure not to press the home button. Also, remember to keep your finger on the home button until you feel a mild vibration (if you are on an iPhone) or until the message changes to "Lift Your Finger".

 5.Adjust your grip. Now is the time to move your finger around different and more awkward ways so that your device can capture your full fingerprint. Try rolling around on your finger while shifting positions, but be sure to keep your finger still while it's "scanning".
6.Optionally, add more fingers. For extra convenience, you can add more fingers such as your left thumb and index finger, and your right thumb and index finger. Keep in mind that you can only register up to five fingerprints.[2]
7.Test it out. Make sure all the options are turned on in the settings and then try locking and then unlocking your device with your fingerprint—it may not work the first time because these are new fingerprints, so just unlock your device with its passcode and try again. If activated in the settings, you can make purchases with your fingerprint on the App Store and iTunes Store, and with Apple Pay.