When a foreigner intends getting Green Card (GK) or an I-551 card of permanent residence, giving him “residence” status and the right to live and work in the USA, he should go thought the AOS process. The abbreviations “hides” the process name — Adjustment of Status. Most of the applications referring to AOSare taken into the process through a person’s employer or through family relations.
A Marriage visa (CR1 or IR1) referrers to immigration visas. The holder of CR1 or IR1, being the spouse of an American, can come to the USA to reside there legally. The types of these visas differ.