Kanhaiya, you can get the model papers of BSEB 2020 exam for 12th board examinations on the given link: http://biharboardonline.bihar.gov.in/model-question-papers-ss

There are two links there: one for Maithli (50 marks) and one for Maithli (100 marks). There are 5 sets of both the papers. You can use them for your board exams preparation. All the best.