Hello Aspirant,

The 10th standard exam by the NIOS examination board will be the best option .. Aspirants whose age is 15 years or above and passed the 8th standard examination can apply inline for this exam. The 8th class certificate, or a certificate acknowledging that you can study at a secondary level would be enough along with other documents. There would be 6 or 7 subjects in total out of which 5 are compulsory subjects and one or two literary subjects.

Click this link to have more data regarding syllabus, application date, subjects, fees structure, important certificates needed, etc.

https://school.careers360.com/boards/nios/nios-admission

I hope it helps.

Thank you