Sindhu you will need to scan both of your mark sheets, the old one and the new one which you must have got after improvement exam. If you haven't got the new mark sheet then also you can download it as a PDF file from the online site and then you need to combine both the files and make it a single PDF file named 12th marksheet that needs to be uploaded on the website before 5th June 2018.

Feel free to ask if you have any more queries. All the best for your JEE Advanced result which is going to be announced on 10th June!!