Hello Ayush,

For getting into fee weaver you haev to first come into opening to closing rank of that particular college 

Since you have not mentioned your desired college you can check the cutoff and see if your rank is lying in between or not  

Then the process is that at time of counselling you fill for fee weaver seat and submit the documents as described by the college 

Here i am sharing a link with you for more of your help 

https://engineering.careers360.com/articles/upsee-cutoff

Hope this help you in a good way  and can ask for more clarification