A visa (short for the Latin carta visa, lit. "the document having been seen") is a permit given by a country that allows someone to go to that country. A visa is often a document that is stamped on a person's passport by an embassy. It names the kind of visit and says how long the person can stay.
If you have a US passport, you can stay in Norway for up to three months without applying for a visa, but you are not allowed to work there. If you want to go to Norway for work or to attend university, then you have to apply for a visa at the nearest Norwegian Embassy or Consulate located within the US.
You must have a passport that is valid for at least three months after the end of your visit. The passport must be issued within the last ten years. You must have valid travel insurance. You must have enough money to finance your stay in Norway and your return journey.
