Population from low-income countries tends to migrate to high-income countries because of different factors:
-They offer a better lifestyle.
-They offer better studies also, it is where you can easily seek highly qualified education.
-They offer better work in urban areas, which will bring in more income. This emigration of highly qualified workers to richer countries is called "brain drain".
-The person could also emigrate because of violence, discrimination or war from the country the person is from.