You can use the official Forgot Registration Number” tool on the NVS recruitment portal. Just go to the site, click that option, and enter details such  as your full name, gender, category, father’s name, mother’s name, and date of burth Once submitted, your registration number  will be emailed or displayed on-screen Or you can also do this way

• Check your email and spam folder for the confirmation message  NVS sent when you first registered
• Try logging in  to the portal using your date of birth and other basic  info to see if it shows your register number.
• Contact NVS support or the exam center with your personal info they can look it up and help you