Hello aspirant. I would like to tell you that you have to fill separately for each course you apply for. As you have mentioned that you have filled the form for btech course, now you need to fill and pay seperately for Bca and bba courses. Also I would suggest you to fill the forms for these courses as a backup plan is necessary. You will have a secondary option if you do not get decent rank in your desired course. I hope you found this answer helpful. Good luck.