How to setup fingerprint ID?

Set up Touch ID

Before you can set up Touch ID, you need to create a passcode for your device.* Then follow these steps:

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. Touch the Home button with your finger—but don't press. Hold it there until you feel a quick vibration, or until you're asked to lift your finger.
5. 
6. Continue to lift and rest your finger slowly, making small adjustments to the position of your finger each time.
7. The next screen asks you to adjust your grip. Hold your device as you normally would when unlocking it, and touch the Home button with the outer areas of your fingertip, instead of the center portion that you scanned first.
8. 

If you have trouble enrolling one finger, try another. Still need help setting up Touch ID? 

Use Touch ID on iPhone and iPad - Apple Support

https://support.apple.com/en-in/HT201371

Did you follow these steps? https://support.apple.com/en-us/HT201371