Migration, as it is used here, refers to emigration from the home country, to settle permanently in another country.
By obtaining the appropriate visa, such as a residence visa, the migrant is able to reside in the new country and become an immigrant resident. The visas here enable a long-term stay, though some conditions may apply to make it permanent. This type of visa status is also commonly referred to as residence, permanent residence (PR) or settlement. It is not the same as citizenship, but citizenship is often available after a period of time residing there.
The Visa Centre can assist in applying for migration/residence/settlement to most countries, or assist in advising on requirements needed. The Visa Centre works in association with other companies and registered immigration consultants, particularly for New Zealand, Australia, Canada and UK.