Visa Waiver Program
Non immigrants from certain countries are not required to have U.S. visas when entering the U.S. as visitors for business or pleasure. Such persons, who must nonetheless still present unexpired passports, are called "visa waivers" shown below as "W.B." and "W.T."
Nonimmigrants, other than persons who enter as "visa waivers", may file applications at the Immigration and Naturalization Service, prior to the departing date, requesting an extension of their nonimmigrant status, or requesting a change to another nonimmigrant status, or requesting adjustment of their status to permanent resident.