Hey prakash

according to NTA

your code will be code2 : if you passed 12th examination from  CBSE/ICSE Board or If you passed from a State Board where 10+2 structure is followed.

you will use Code 3: if you studied your Class 12 as a Pre-University Course student/Pre-degree Course student/Junior College student, ie. your Intermediate/Pre-degree Examination in science under any Indian University/Board. The PUC qualifying exam takes place in very few states like Karnataka.

for more information go through the following link:

https://medicine.careers360.com/articles/neet-qualification-codes

hope this helped.

all the best