M.S

There are opportunities for doing integrated Ph.D. especially in institutions like TIFR, IITs and IISc one may also pursue a Ph.D. after a post graduation and qualifying NET or equivalent. You may visit https://www.ncbs.res.in/academic/int-phd.

It is difficult to beat Fordham University, if you want to study Finance & Financial Management. In addition to its Bachelor's programs, Fordham University offers graduate degrees in Finance. Pace University - New York offers graduate degrees in finance for those interested in an advanced degree.

Please refer the link below for more details:
https://studyabroad.shiksha.com/ms-in-agriculture-from-abroad-ds11509292.

Follow the link below for all the details:
https://studyabroad.shiksha.com/search-abroad/?q=MS&co[]=8&ds[]=1509&qer=yes&tid=2752637&ref=searchPage
Copy/paste the entire link on the browser.

Do you mean Post-Graduate studies in Business?

Both are same. The only difference is, MS is university approved while PGDM is college university.

Yes, depends on the programme and university admission requirements. It may be difficult to apply to US and Canada since you have a 3 year degree. Just check admission requirements, course requirements and proceed accordingly.

For F1 status Visa, you will have 60 days to leave USA after the course ends.

Of course, you do. It depends on the stream you are interested in.

Well, that depends on whether you want to do MS or MBA. GRE is for MS and GMAT is for MBA. Apart from that, the course you select determines which country to opt for. For example if you are looking for automotive courses, Germany and UK is the best option. On the other hand, MBA is good in USA, Canada and UK too. This is just my opinion. So, what you should do is browse through different courses in different countries and select one that suits you best.