Hello aspirant,

Depending on the board and whether it's for regular school or NIOS (National Institute of Open Schooling), the deadline for 10th class (Class 10) admissions varies.  Registration for normal board exams, such as the MPBSE or CBSE, usually takes place in the months preceding the exam period, which is often February or March.  Admissions to NIOS for the April term are normally free until July 31st, after which there will be late fees.

Thank you