In order to legally stay in South Korea for a period of more than 90 days, every foreigner is required to apply for a visa and obtain an identity card called a Residence Card, formerly known as Alien Registration Card (ARC). The residence/alien registration card must be applied for within the first 90 days of entry upon arrival in Korea. In addition, renewal of the residence/alien registration card is mandatory for those who wish to extend their stay or change their visa.