The company organising your VISA should send you out a detailed list of everything you need for your VISA appointment however if they haven’t this is what you will need:
Your Passport
A printout of your appointment confirmation email from the US Embassy
A print out of your payment receipt that came with your appointment email
Your DS-160 form that you completed online prior to the Embassy appointment. Make sure the barcode is visible on the printout
Your DS-2019 form signed and dated
Your SEVIS I-901 Fee, you will need to print this yourself
Documentary evidence/proof of return documents.
Your VISA photo