Code 1 is for candidates who are appearing for Class 12

Code 2 is for candidates who have completed 10+2

Code 3 is for candidates who have passed or studying for any degree in science stream

Code 4 is for candidates who have completed 10+2 and degree with physics, chemistry, Biology/Biotechnology

Code 5 is for candidates who are in the first year of B.Sc. or any course similar

Code 6 is for candidates who have passed their B.Sc. with the PCB subjects

Code 7 is for students who have completed studies similiar to 10+2 of Indian education board

You can refer to this article for more information

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

Best of luck