People who want to become immigrants based on family are divided into “preferences” (categories), and if their immigrant visa petition is approved, they must wait for an immigrant visa number to become available according to the preference system. An exception exists for immediate relatives of U.S. citizens, which includes parents, spouses and unmarried children under the age of 21, who do not have to wait for an immigrant visa number to become available once the immigrant visa petition filed for them is approved. An immigrant visa number will be immediately available for immediate relatives of U.S. citizens.
The relatives in the remaining categories must wait for a visa number to become available according to the following preferences:
First Preference: Unmarried, adult sons and daughters of U.S. citizens. Adult means 21 years of age or older.
Second Preference: Spouses of lawful permanent residents, their unmarried children (under age 21), and the unmarried sons and daughters of lawful permanent residents.
Third Preference: Married sons and daughters of U.S. citizens.
Fourth Preference: Brothers and sisters of adult U.S. citizens.
Once USCIS receives your visa petition, I-130, Petition for Alien Relative, it will be approved or denied. USCIS will notify the person who filed the visa petition if the visa petition is approved. USCIS will then send the approved visa petition to the Department of State's National Visa Center where it will remain until an immigrant visa number is available.
Because of the number of immigrant visa numbers that are available each year is limited, you may not get an immigrant visa number immediately after your immigrant visa petition is approved. In some cases, it could take several years.
The National Visa Center will notify you, the foreign national, when the visa petition is received and again when an immigrant visa number is available. You do not need to contact the National Visa Center unless you change your address or there is a change in your personal situation, or that of your relative, that may affect eligibility for an immigrant visa, such as reaching age 21, marriage, divorce, or death of a spouse..