Hi sakshiagarwal311,
From your message, it's not clear whether you're just beginning your studies or you've been studying for some time. There are a variety of different study materials that you might choose to use, so before we discuss what Course might suit you best, it would help if you could answer a few questions about your studies so far and your goals:
1) Have you done any studying so far? If you have, then what materials have you used?
2) What is your goal score?
3) When are you planning to take the GMAT?
4) When are you planning to apply to Business School and what Schools are you planning to apply to?
If you're just beginning your studies, then it would be a good idea to take a FULL-LENGTH practice CAT Test; you can access 2 for free from
www.mba.com (and they come with some additional practice materials). If you want to do a bit of practice first, so that you can familiarize yourself with the general content and question types first, then that's fine - but you shouldn't wait too long to take that initial CAT. A FULL CAT takes about 3.5 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have your Score, you should report back here and we can discuss the results and come up with a study plan.
GMAT assassins aren't born, they're made,
Rich