Hello Aspirant,

See registration number and roll number are two different numbers and in NEET UG application form you need to mention your roll number not registration number and roll number is the number that will be mentioned on your class 12th Admit card, if you are from CBSE board the CBSE has already issued admit cards to class 12th candidates so you can put your roll number from there and if from any other board and did not get the admit card then you can leave the section of roll number. For class 11th it's your choice whether you want to fill it or not because it is optional section, if you want to fill it, then fill otherwise you can also leave it.

To get live updates and complete details about NEET UG application kindly visit the link given below :-

https://medicine.careers360.com/articles/neet-application-form

You can also solve the Test series for NEET UG 2022 for better finishing of your preparation, you can get the Test series from the link given below :-

https://learn.careers360.com/test-series-neet-may/

I hope this information helps you.

Good Luck!!