Why Autofill wasn't possible previously?
Most of us know that Apple gives at most maintenance for user privacy. As soon as we see iOS structure, every individual program is like a distinct island. There's no inter-app bridge between programs (exception for Keychain and URLSchemes APIs that gives very limited scope). Thus we can't read content material from inbox.
Where to begin Autofilling?
First of all, the goal SMS need to possess the OTP Code with prefix string"Code" or"Passcode"on its message content. Beware of OTP code approved only when it has no space and functions only with system supplied keyboard. Don't expect this feature works with custom computer keyboard.
Currently from the application side, make certain that device running in iOS 12 and set text field content type into'.OneTimeCode'.
This can be also accomplished via storyboard. Just select UITextField in storyboard/XIB and click Attribute Inspector. Keyboard Type does not matter. As given in the first diagram, as soon as a SMS using OTP code obtained in the message inbox, then we'll see the same in the tool bar of the Computer Keyboard. We all will need to tap into the code to get autofill OTP area.