Who is an expatriate? Well, it's just an exile or, in other words, a person who lives in another country. Some people become expats because they have to, other because they want to.
These are the four ways you can become an expat:
Once you do become an expat... you have to learn how to live in another country, You need to learn its language, culture, etc. Hence, if your employer makes you become an expat, they usually want to make up for this by offering you all sorts of benefits. Here's a page that will enlighten you on this...
My question to you:
Would you like to be an expat? Which of the four ways would you choose for yourself? Why?