The admit card will have the details the way you have filled in NEET application form. If you have mentioned your Surname in the NEET application form, it will be printed. But if you have missed in entering your Surname in the application form, it will not be shown on the Admit card. Then you cannot ask NTA for corrections because once the correction window has been closed NTA neither will entertain any corrections nor will it make changes to your application. But if you did mention the Surname and it does not appear on the NEET admit card, then you can reach out to the helpdesk. They will look into it and make note of this so that you will not face any issues regarding security check in the day of the examination.