For example, you can work in the US for a 1-3 years after your education without needing a work permit.
There are number of opportunities in different countries. I would recommend thinking about your goals first. If you intend to work in the country where you study, learn about the immigration policies for that country. Some countries have lenient work permit and immigration policies while some countries may have good schools but their work permit rules are stringent. For example, you can work in the US for a 1-3 years after your education without needing a work permit. However, you need H-1B visa to work in the US after that and that is based on a lottery system.