Hello Sayed. You can read the instructions in the link below and apply for improvement exam. I don't think there is an option to appear for only 2 subjects. You can confirm it with the officials though. Good luck.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://maharesults-nic.in/class-improvement-scheme-hsc-maharashtra-2019-online-form/&ved=2ahUKEwio-tuKvPriAhWIYisKHS0GBB4QFjALegQIAxAB&usg=AOvVaw3mooCXXVfkQKXvL96F_kfn&cshid=1561116646229