The past simple - 'I moved' - refers to a fixed and finished time in the past. So, for example, you might say: 'In 2012, I moved to Canada for a few months to improve my English.'* 'When I was a student, I moved to Canada for a few months to improve my English.' 'I moved to Canada for a few months to improve my English. But then I went back to Brazil'. These are all finished or 'closed' periods of time. If the period of time is still 'open', you could use the present perfect: 'I've moved to Canada for a few months to improve my English.' 'I've moved..' would suggest that you moved to Canada fairly recently and that you are still in Canada now. You might use this as an explanation about why you are no longer in your own country. * Note that I've corrected the construction in the second half of your sentence. The word 'for' should come before 'a few months.' Finally, here's a general tip that works most of the time: If you aren't sure whether to use the past simple or present perfect, choose the past simple - it is far more likely to be correct in the majority of cases.

I moved to Canada