What does it mean that the traffic management applicant 12 123 received the verification code?

That's the reservation verification code.

The transportation service management platform is a general reservation platform in China. After opening this website, select the corresponding province and click to enter the online platform of the Traffic Management Bureau of the Public Security Department. There is a green exam reservation button on the homepage of the platform. Click the exam reservation button to enter the login page, click Register Now at the bottom of the page to register the online vehicle management account, and follow the steps to display it. After successful registration, you will have your own online vehicle management account. Click the business processing button at the top of the login account. On the business processing page,