What's the difference between the I-130 and the I-485 applications?

Question

What's the difference between the I-130 and the I-485 applications?

Answer 1

I-130 is a petition for an alien family member.

I-485 is a request to change the immigration status for a person who is already within the United States.

For instance, an American citizen brings his fiancee to the United States on a fiancee visa.  The fiancee visa is a non-immigrant visa.  After they get married the wife will file an I-485 to change her status from non-immigrant to immigrant.