I am fail in 12th this year then i am doing again 12th so how can i fill the jee main form....plz tell me..

Hello Dear
Don't need to be panic about that eventhough you are failed in class 12th eventhough then also you can definitely able to fill up the JEE MAINS form for next year but make sure inorder to get in the good colleges via JEE Mains or other engineering entrances exams for that you need to score atleast of 75% in Class 12th. At the time of filling the JEE form you need to fill  all the current details like medium of board, school name and as a appearing candidate.

All the best

Hello,
You can appear for jee mains next year also.And you should fill in the column as 12th appearing as you haven't passed class 12th board exams yet.
Good luck.