If you are asking to fill for JEE Main application form you should submit a correction request at Aadhaar centre to apply for the application form.and apply for JEE (Main) by entering 14 digits Aadhaar Enrolment ID/UR No. (Including slash) printed on the slip issued by aadhaar centre after submitting updation request.

Or

You should candidates should fill the form of JEE (Main) with old details in Aadhaar card and thereafter submit a correction request at Aadhaar centre. The updated details in Aadhaar may be corrected in JEE (Main) at later stage by the process which will be notified in due course of time.