i am in class 12th this year what is code for apply form

Hello dear

I assume, you are asking for NEET Entrance Exam. You should use code 01 , since you are appearing for 12th board this year.

all the best dear !!!

It will be 01. Code 01 says: A candidate who is appearing in the qualifying examination, i.e., 12th Standard in 2020, whose result is awaited, may apply and appear in the test but he/she shall not be eligible for admission to the Undergraduate Medical Courses, if he/she does not pass the qualifying examination with the required pass percentage at the time of first round of Counselling.

But your admission will be provisional subjective to your 12th final results.