Hii Gourav !

If you are from Rajasthan, madhya Pradesh, punjab, Jharkhand, then class 8th results are published officially on their respective education portals ( since they conduct a state level exam for class 8th ).  You can enter your roll number and see your result

But for most of the other boards, you won't be able to find it on the state / national board site - you will have to check your school's notice board, online portal or contact the school directly for result related notifications.

Hope it helps :)