Manage Touch ID fingerprints
Use Touch ID to securely and conveniently unlock iPhone, iPad, or Mac, authorize purchases and payments, and sign in to many third-party apps by pressing the Home button with your finger or thumb.
To use Touch ID, you must first set up a passcode on your iPhone, iPad, or Mac.
IMPORTANT: Before making changes or deleting information, consider potential impacts to your safety and privacy.
Secure your devices with Touch ID
To use Touch ID, you must first set up a passcode on your iPhone or iPad.
Find out how: To view a task below, select the plus button 
next to its title.
Set up Touch ID on your iPhone or iPad
If you didn’t turn on fingerprint recognition when you first set up your iPhone or iPad, go to Settings
> Touch ID & Passcode.Turn on any of the options, then follow the onscreen instructions.
Note: If you can’t add a fingerprint or unlock your iPhone or iPad using Touch ID, see the Apple Support article If Touch ID isn’t working on your iPhone or iPad.
Set up Touch ID on your Mac or Magic Keyboard
To use Touch ID, you must first set up a password on your Mac.
Choose Apple menu
> System Settings, then click Touch ID & Password 
in the sidebar.Click Add Fingerprint, enter your password, then follow the onscreen instructions.
If your Mac or Magic Keyboard has Touch ID, the sensor is located at the top right of your keyboard. You can add up to three fingerprints to your user account (and you can save up to five fingerprints total on your Mac).
Click the checkboxes to select how you want to use Touch ID:
Unlocking your Mac: Use Touch ID to unlock this Mac when you wake it from sleep.
Apple Pay: Use Touch ID to complete purchases you make on this Mac using Apple Pay.
iTunes Store, App Store & Apple Books: Use Touch ID to complete purchases you make on this Mac from the Apple online stores.
Password AutoFill: Use Touch ID to automatically fill in user names and passwords and to automatically fill in credit card information when requested while using Safari and other apps.
Use Touch ID sensor for fast user switching: Use Touch ID to switch Mac user accounts.
Delete unknown Touch ID fingerprints from an iPhone or iPad
If there are multiple Touch ID fingerprints on your iPhone or iPad, you can delete them to help safeguard access to your device.
Go to Settings
> Touch ID & Passcode.If more than one fingerprint is available and they are unnamed, you can place a finger on the Home button to identify your finger’s print. Consider naming your fingerprint to help you identify it later.
If necessary, tap the fingerprint, then tap Delete Fingerprint.
Note: If you can’t add a fingerprint or unlock your iPhone or iPad using Touch ID, see the Apple Support article If Touch ID isn’t working on your iPhone or iPad.
Delete unknown Touch ID fingerprints from a Mac or Magic Keyboard
If there are multiple Touch ID fingerprints on your Mac or Magic Keyboard, you can delete them to help safeguard access to your device.
Choose Apple menu
> System Settings, then click Touch ID & Password in the sidebar.Do any of the following:
Delete a fingerprint: Click a fingerprint, enter your password, click OK, then click Delete.
Add a fingerprint: Click Add Fingerprint to add new fingerprint, then choose which options you want to use with Touch ID.