Formal:
* Immigration: This word refers to the act of moving to a new country to live permanently.
* Emigration: This word refers to the act of leaving one's country to live in another.
Informal:
* Arriving: This is a basic and neutral word that simply describes the act of reaching a new country.
* Landing: This word is often used when referring to arriving by airplane.
* Entering: This word emphasizes the act of crossing the border into a new country.
* Coming to: This is a simple phrase that can be used to describe arriving in a new country.
* Moving to: This emphasizes the act of starting a new life in a new country.
More descriptive:
* Settling in: This word implies the process of adapting to a new country and establishing a life there.
* Making a home: This is a more emotional word that suggests finding a place of belonging in a new country.
The best word to use will depend on the specific situation. For example, if you are talking about a person who has just arrived in a new country to live, you might use the word "immigration" or "settling in." If you are talking about a person who is visiting a new country for a short time, you might use the word "arriving" or "landing."