PK 4 docs
1. Interview appointment letter
2. List of Doctors for medical exams on the country of interview
3. Forms DS 230-1 and DS 230-2
4. Form I-864 affidavit if Family IV
5. Form I-134 Affidavit for derivatives relatives (Spouse,Children) usually the consulate do not send you this form but you can downloaded from INS site.
6. Form 9003 for IRS
7. Instructions for the interview, bring Photos, police certificates, birth certificates, marriage certificates, divorce certificates, adoption certificates, Notarized COMPANY LETTER, Tax returns, stubs, I-140 approval notice I-797.