1.2 Greeting

There are several words that can be used when you are greeting another person:

Hei is informal and quite common. In general, one is using hei in face to face communication with friends, but also the first time you meet a stranger.
Hallo is informal and rather common as well. In general, one is using hallo when talking on the telephone, but also in face to face communication.
God dag (literaly, good day) is a bit more formal, most used by adults when greeting strangers and less acquainted people.