Dear Preethi, 

If you can produce the original Certificate that would be very beneficial. 

But since you don't have it, the last hope is its copy. 

Therefore you should upload the copy. 

Moreover when you upload the document ,it is a copy so you don't need to worry so much. 

But be sure that the Xerox's content is uploaded carefully .

If you want to know about the colleges that you will get, you can try Careers 360 College Predictor

https://engineering.careers360.com/jee-main-college-predictor