4 Visas allow the Spouse and Spouse's children (unmarried children under 21) enter the United States to await the approval of the I. 130 petition by USCIS or the availability of an immigrant visa. citizen, who is waiting abroad for an immigrant visa, and the (K. 4 Visa) spouse's children to enter the United States as nonimmigrants, re. unite with their family here, and then apply for immigrant status while in the country. It is one of several immigration benefit provisions created by the Legal Immigration Family Equity Act (LIFE Act).