For certain U.S. visas, specifically, a B-1/ B-2 visitor visa (commonly known as a tourist visa), the DS-160 online application is the most important part of the U.S. visa process. Not only does the DS-160 require important personal information needed for a consular officer to adjudicate the visa application, it is the only document that the consular officer is required to review when determining if a person is eligible to receive a U.S. visa.
In the event that a person is refused a U.S. visa under Section 214(b) of the Immigration and Nationality Act, the DS-160 can also be used in a subsequent application to demonstrate that the U.S. visa applicant has sufficient ties to their home country in order to overcome their previous refusal. For example, the DS-160 specifically asks if an applicant has ever been refused a visa and provides space in order to explain the circumstances. Since the DS-160 does have a maximum number of characters that can be used, applicants are free to write in enough information as necessary to explain the events of the previous application and refusal which will hopefully give the consular officer a better understanding of the previous interview(s). Such explanation can be further used to show that the U.S. visa applicant has sufficient ties outside of the United States to which he or she would return and that would hopefully enable them to overcome a further refusal.