CR1 is for spouses of U.S. citizens married for less than two years, while CR2 is for their unmarried children under 21; IR1 is for spouses of U.S. citizens married for two years or more, while IR2 is for their unmarried children under 21.
U.S. citizens residing in the United States must submit their CR/IR applications to the immigration service center in their jurisdiction. CR1/IR1 are immigrant visas. Within 1-3 months of entering the United States, you will receive either a two-year conditional Green Card (if married for less than two years from the date of marriage to the date of entry) or a ten-year Green Card (if married for more than two years) sent by the USCIS to your U.S. residence.
U.S. citizens may also apply for CR2/IR2 visas for their children (stepchildren of the U.S. citizen) separately. However, in the following cases, you cannot apply for a visa; you must wait until you have naturalized as a U.S. citizen before you can apply for a visa for your child yourself:
a. The child was over 18 years old when you married the U.S. citizen;
b. The child is over 21 years old at the time of application;
K3 is the priority category for CR1/IR1, and K4 is for unmarried children under 21;
Regarding the CR1/IR1 application, once you have received the receipt notice from the USCIS, you may choose whether to apply for a K3 simultaneously. K3 is a visa category created by the U.S. immigration authorities, considering the long processing time for CR1/IR1, to allow spouses to reunite as soon as possible by applying for a K3 to enter the U.S. early.
Although you must apply for CR1/IR1 first, K3 and CR1/IR1 are two independent cases, each with its own processing procedure. If the processing speed of CR1 is similar to that of K3, the CR1 and K3 cases will be merged, and you will directly attend the CR1 interview to obtain permanent residency upon entering the United States. Otherwise, you may first attend the K3 interview at the U.S. Consulate General in Guangzhou to enter the United States and reunite with your spouse, and then choose to adjust your status within the United States to obtain permanent residency.
