We have a mobile application. To register in our application you need to enter your phone number. After that, you receive an SMS with a code you need to enter to confirm your phone number.
There is a system which automatically takes the code from the received SMS and substitutes it to the field where the code should be inserted. But this system doesn't work in all countries, which is why there is a option to enter the received code manually.
When the system works and code is automatically substituted, users usually don't understand what just happened and why the "Enter PIN" screen suddenly disappeared.
So the problem is: how to show to user that code was automatically taken and everything is fine?
Just show a popup with successful message afterwards.
Insert code in the field automatically, but ask user to push "Verify" or "Enter" button manually.
Which one is more efficient or are there any other suggestions?