Thank you for the information @SOA,
Can you confirm if you've gone through the phone's settings to make sure the Face ID is properly enabled and that the right permissions were given to grant access to the My Account App?
Do you get an error message when you try to use this feature, or is it simply not appearing as one of the available options?
You can definitely activate Touch ID for the Fido app on iPhone
To do so, first make sure you're logged in and then follow these steps:
1.Tap "More" on the bottom right
2. Tap "Your Profile & Settings"
3. Tap "Settings" at the top
4. Select "Enable Touch ID" to activate
I hope that helps! For those with an iPhone X or newer the exact same steps apply to activate Face ID.