If you've passed 12th class in 2025 and reappear in 2026 without going to school then you can apply as a private candidate through your school GSEB repeater's form, these are usually updated and made available online on the official website. you will just need your previous marks and other id proofs.

if that's not the case and you are right now in class 12 and you will appear your board exam in 2026 It would be good if you do inquiry in your school and look for any private or regular student through your college via open or private schooling if eligible, and prepare for Jee.