Why doesn't the iphone SMS verification code fill in automatically?

Not auto-filling means that the auto-filling function is not turned on or the verification code does not match.

First of all, you need to make sure that the auto-fill function has been turned on in the settings of iPhone. Please open the settings, click the password and account number, and then enter the option of automatically filling in the password to ensure that this function is turned on. Secondly, if the input verification code does not match the verification code sent to the mobile phone, it may not be filled in automatically. This may be due to network delay or other reasons that the verification code cannot be automatically filled in the input box. In this case, you need to manually enter the verification code to complete the verification process.