I'm mechanical engineer working in design field,is MBA a better option If yes which MBA course would be better (finance,marketing,operation)

There are 2 things that I would like to say about...there is no assurance that you would get a better prospect unless you get a MBA offer from top b-schools such as IIM- A,B,C, etc w.r.t. design roles pertaining to MBA...another thing is there are several courses such as master of design which is present in IIT, Delhi w.r.t. M.Tech. which can help you to get better opportunities in case you want to pursue a career in design only...I would suggest that you decide whether you really want a technical related role or a MBA related role and take your decision based on that...I hope this answer helps you

Which stream you want to do major specialization while pursuing MBA degree all depends on your interest. It does not matter whether you are an engineer or non engineer or in which stream you have completed your graduation.

Doing MBA is open to all and a student like you who have a work experience in working field will be very good because you will be able to understand the problems in a better way and come up with a managerial solutions for them. Also after MBA exams when any college prepares a merit list to call students for next round on the basis of your aggregate score then you will also get additional marks because of your work experience.

See as I told earlier which stream you need to go depends on your interest and you will evem get a year in college to study subjects from all streams so that you can recognise in which you are most comfortable and want to do build up career by doing major in second year.

On my personal note operations could be a good one becuase you have a live field and designing experience so you can use management learning to enhance yourself in that field. But still it will always be your choice.

All the best!!

MBA is a good option but I can't say whether it's the best option or not. For now dong think about what domain you should get into. Get into a good college and then see what you like. Depending upon your background operations might be good for you but the thing is that you might get shortlists for sales and marketing too. So, you should keep your options open.