You must complete and submit the DS-160 online. Clicking the "submit" button constitutes the applicant's electronic signature.Cn to fill out the form online. 797 form cannot be used instead of a valid visa. Applicants must have an Advance Parole stamp already in the passport at the time of the visa application. SIGNED U.S. PASSPORT - MINIMUM OF 6 MONTHS REMAINING VALIDITY WITH AT. LEAST 2 SIDE-BY-SIDE BLANK VISA PAGES. 2.) ONE CURRENT PASSPORT-TYPE PHOTOGRAPH (2X2):. Application for visa must be submitted in person with no more than 180 days in advance to your trip and at least 15 days before. The scammers behind these fraudulent emails and letters are posing as the US government in an attempt to extract payment from DV applicants. You will then receive an acknowledgement letter containing the official Application Reference Number via email.