While filling up n-school form the most important thing is career objectives becuase it defines why you actually want to do MBA and how focussed you are for it.

If you have any objective of doing MBA other than securing a job with a fat package make sure you mention it. If not then you can mention your interest in one of the stream say you like marketing and you want to excel yourself in that field. If you have any work experience in any of the field than you can mention that you want to do MBA and along with your prior technical skills knowledge you want to excel in that department.

And in the end of none option like that then you can say that in the long run you want to serve in x field (mention any interesting field like education) and open up your own venture so for that you need to have good management skills. Although it may not be true but creates a good impression.

Whatever you write make sure you remember it and study a little about it because there is a good chance that in interview they might Google you to check out how much you mean it.

All the best!!