Adding Touch ID support
QWhich Macs support Touch ID? How can I get my iMac 27-inch to use it?
AFingerprint recognition in Touch ID requires an ARM processor, provided in an Intel Mac by either a T1 or T2 chip, or in an Apple silicon Mac, together with a keyboard with a built-in fingerprint sensor.
Touch ID is a standard feature of MacBook Air and MacBook Pro notebooks with a supporting ARM chip, where the sensor is built into their internal keyboard. Although recent Intel Mac minis and iMacs have T2 chips, according to Apple those models aren’t compatible with its Magic Keyboards equipped with a Touch ID sensor.
The situation is different with Apple silicon Macs. Again, MacBook Air and MacBook Pro models come with the sensor built into their internal keyboards, but you’ll need to buy one of Apple’s Magic Keyboards with Touch ID included if you want to use it with an iMac, Mac mini or Studio. For that you’ll pay a premium of at least £50 on top of the cost of the basic keyboard, even more if you want the larger version with a numeric keypad. There doesn’t appear to be any alternative to Apple either.
Your Intel iMac doesn’t currently support Touch ID; the most likely way to gain that facility is to replace it with a new Apple silicon model, assuming that you pay extra for its keyboard.