You can use Touch ID with an iPhone 5s or later, iPad Pro, iPad Air 2, or iPad mini 3 or later.

Set up Touch ID

1. Make sure that the Home button and your finger are clean and dry.
2. Tap Settings > Touch ID & Passcode, then enter your passcode.
3. Tap Add a Fingerprint and hold your device as you normally would when touching the Home button.
4. Continue to lift and rest your finger slowly, making small adjustments to the position of your finger each time.

If you have trouble enrolling one finger, try another.

Use Touch ID to unlock your iPhone or make purchases

After you set up Touch ID, you can use Touch ID to unlock your iPhone. Just press the Home button using the finger you registered with Touch ID.

Make purchases with Touch ID

You can use Touch ID instead of your Apple ID password to make purchases in the iTunes Store, App Store, and iBooks Store. Just follow these steps:

1. Make sure iTunes & App Store is turned on under Settings > Touch ID & Passcode. If you can't turn it on, you might need to sign in with your Apple ID in Settings > iTunes & App Store.
2. Open the iTunes Store, App Store, or iBooks Store.
3. Tap something to buy. You'll see a Touch ID prompt.
4. To make a purchase, lightly touch the Home button.

Use Touch ID for Apple Pay

With an iPhone 6 or iPhone 6 Plus or later, you can use Touch ID to make Apple Pay purchases in stores, within apps, and on websites in Safari. You can also use Touch ID on your iPhone to complete website purchases from your Mac. If you have an iPad Pro, iPad Air 2 or iPad Mini 3 or later, you can use Touch ID for Apple Pay purchases within apps and on websites in Safari.

Manage your Touch ID settings

Go to Settings > Touch ID & Passcode to manage these settings:

• Turn Touch ID on or off for Passcode, iTunes & App Store, or Apple Pay.
• Enroll up to five fingerprints. Each new print might make fingerprint recognition take slightly longer.
• Tap a fingerprint to rename it.
• Swipe to delete a fingerprint.
• Identify a fingerprint in the list by touching the Home button. The matching print in the list will be highlighted briefly.

In iOS 10, you need to press the Home button using Touch ID to unlock your device. To unlock your device using Touch ID without pressing the Home button, go to Settings > General > Accessibility > Home Button and turn on Rest Finger to Open.

Get help with Touch ID

You might need to enter your passcode or Apple ID instead of using Touch ID for one of these reasons:

• If you've just restarted your device
• If your fingerprint isn't recognized five times in a row
• If you haven't unlocked your device in more than 48 hours

• If you've just enrolled or deleted fingerprints
• If you're trying to open Touch ID & Passcode in the Settings menu

If you still need help, follow these steps. Try using Touch ID after each step:

1. Make sure that your fingers and the Home button are clean and dry. For the Home button, use a clean, lint-free cloth to wipe off any dirt or debris.
2. Your finger should cover the Home button completely, touching the surrounding metal ring. While Touch ID is scanning, you shouldn't tap too quickly or move your finger around.
3. If you're using a case or screen protector, make sure it doesn't cover the Home button or the surrounding ring.
4. Go to Settings > Touch ID & Passcode and make sure that iPhone Unlock or iTunes & App Store is on, and that you've enrolled one or more fingerprints.
5. Try enrolling a different finger.
6. If you can't enroll any of your fingers, take your device to an Apple Retail Store or Apple Authorized Service Provider, or contact Apple Support.

1 Moisture, lotions, sweat, oils, cuts, or dry skin might affect fingerprint recognition. Certain activities can also temporarily affect fingerprint recognition, including exercising, showering, swimming, cooking, or other conditions or changes that affect your fingerprint.

Source: support.apple.com