The immigrant visa case number is displayed at the top portion of the Immigrant Data Summary issued by United States Citizenship and Immigration Services. Your DOS Case ID number is listed underneath the A-Number and is a 10-digit number preceded by three large case letters, explains USCIS. The Immigrant Data Summary is part of a visa package, and it's the first document on top. The case number also appears on other official documents.
The USCIS Immigration Fee document also features your DOS Case ID number, and you can locate it in the upper right-hand corner. This handout is given to visa applicants during an interview with the U.S. consulate or embassy, states USCIS. If you have already been issued an immigrant visa by the United States, your case number is stamped onto the document and located in the upper-right corner under the heading Immigrant Visa. After locating the number, keep a copy of it somewhere secure for easy retrieval in the future.
The USCIS only issues a visa case number after a relative or employer petitions the agency on behalf of a person seeking immigrant status, according to Findlaw. Once a visa number is available, and the petition is approved, the National Visa Center notifies the beneficiary. Visa numbers are issued in order of preference, and first preference for families goes to the unmarried adult children of U.S. citizens. For employment, first preference goes to people with exceptional skills and talent.