Hi,
MCI registration is for the professionals who have completed their MBBS. Since, you are in sixth semester, you are not eligible for the registration right now. You can register for the same when you will complete your MBBS and will get your degree. You will able to upload your marks for online semester then only. If you have any more questions, you can ask in the comment section.
I hope this helped you. All the Best!
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile