A fingerprint appointment is scheduled with the U.S. Citizenship and Immigration Services when a person is applying for his green card and naturalization. This is done for the purposes of an FBI background check.
After the USCIS receives a person's application, the department sends the applicant an appointment letter outlining the nearest location of an USCIS-authorized fingerprint site. Applicants who submit a fingerprint card directly with their applications are automatically rejected.
Once the applicant has attended his appointment and had his fingerprints processed, USCIS sends the prints to the FBI for analysis. If the FBI rejects the fingerprints, USCIS notifies the applicant, and another appointment is scheduled.