At first, I have a same problem as this question How to show verification code suggestion on keyboard from Message, then when I received a message containing Your one time password is 123456, the passcode was suggested in my keypad, the case is, I don't know what is the proper format of the sms that I need to received, where can I see the certain documentation or rules and instructions for the readable sms OTP?
In my given link, they gave a video link, but for some personal reason, I can't watch it.
Here is the documentation about password autofill. It says to actually test it out yourself by sending out a text message:
To test the format of your SMS code for different languages, text a message to yourself. If you receive a message with an underlined security code, tap on the code. If a Copy Code option appears, the system has recognized your code.
However, from other developers who have tested out it seems SMS containing these formats work fine:
your passcode is:123456
or
12345 is your code to log in.