Click on this link to learn how to 'Use Touch ID on iPhone and iPad --> Use Touch ID on iPhone and iPad - Apple Support
- "You can use Touch ID with an iPhone 5s or later, iPad (5th generation and later), iPad Pro, iPad Air 2 or later, and iPad mini 3 or later." [Used to say that but now doesn't mention system requirements.]
- 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 Apple Books."
- "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."