Hello,

Bihar board has not yet released the syllabus for year 2022, it is about to release on their official website ie. biharboardonline.bihar.gov.in.
The exams for year 2022 are likely to be held in february 2022, you can get an idea about the syllabus from last year's syllabus of Bihar board.

Here I'm attaching a link from where you can see previous year Syllabus of board.

Here is the link for the same:
https://school.careers360.com/articles/bihar-board-12th-syllabus



Hope this helps, all the best.