Few weeks before your interview the USCIS will send you an Interview Notice and ask you to appear at a local immigration office for your green card interview. The USCIS Interview Notice will list all the documents and information you must bring with you to the interview. The USCIS Interview Notice normally requires that you bring with you all copies AS WELL AS ORIGINAL DOCUMENTS that were submitted with your application such as: Passport, Birth Certificates, Marriage Certificate, Divorce and Death Certificates, updated financial documents for the Affidavit of Support, documents showing that you and your US Citizen Spouse have been living together and trust each other, such as utility bills, bank statements and credit card statements and anything else to establish that your marriage are real marriage and that the marriage was entered into in good faith.
You should contact a US Immigration Lawyer in order to prepare your file for the green card marriage interview.