USA

Hello,
Some of the best ones are:
MIT
Georgia Institute of Technology
Carnegie Mellon University
University of California- Berkeley
California Institute of Technology
NYU
to name a few.

Hi Udayan,
Focus on your academics and study hard. Excellent percentile is required. Additionally, you must demonstrate an all-rounded profile that is taking part in extra curricular, project work, research, community or voluntary work. MIT is one of the toughest universities to get into and you need to prepare hard. A very good SAT score ( 1450+) is recommended. SAT subject tests are also required. You are also required to take the TOEFL. I will also advise you to visit the MIT admission webpage and see what all it takes to be an MIT student. All the best.

Hi Varghese,
You can check the link below and find colleges in USA and other countries within your budget:
https://studyabroad.shiksha.com/mba-in-abroad-dc11508

After graduation, you can prepare for GMAT/GRE. Score around 318-320 in GRE is good enough to get into top US universities for MS. After MS, you can start with internship and job.

You must have a Bachelor's degree in the same field and also if you are good in academics, it will be a bonus for you.

Hi,
The GRE and TOEFL must be taken. Also, you must check if a 3-year B.Sc will be accepted or not, in the latter case a WES evaluation will be required.

Hi Kavya, US is home to some of the famous universities such as
University of California Berkeley
University of California Los Angeles
Carnegie Mellon University
MIT
Georgia Tech
California Institute of Technology
University of Pennsylvania and so on.