Hello  Aspirant,

You can find in many websites or books will be available for this kind of examinations. You can visit the official website for seeing previous papers and try writing mock tests.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.nios.ac.in/student-information-section/question-paper-of-previous-year-examination-academic.aspx&ved=2ahUKEwi7msj26eTnAhXNwjgGHcgxCzsQFjAAegQIAhAB&usg=AOvVaw0LL5o4JBKmf8k3sRp3aRiq

This is officail website. Hope this is useful