What is the ESTA visa?
ESTA is the abbreviation of Electronic System for Travel Authorization. As part of the US Visa Waiver Program, the ESTA Regulation was adopted by the DHS - Department of Homeland Security on November 7, 2008 and on January 12, 2009.
The introduction of the Electronic Systems for Travel Authorization Portal for the early determination of whether legal or state security threats emanate from a US traveler was passed in direct connection with the law of the Investigation Commission as of September 11, 2007.
An ESTA Visa Waiver does not constitute a full visa. It does not meet any legal requirements to be used as a visa substitute. However, travelers from countries eligible for the ESTA VWP program may apply for an ESTA visa online up to 72 hours prior to departure and, after successful approval, travel to the United States for up to 3 months at a time.
Holders of a valid ESTA permit are required to complete a blue customs declaration at the Port of Entry upon arrival in the U.S., but do not need to complete the green I-94 W card.
Holders of a valid visa do not need an ESTA. In both cases, i.e. for holders of a visa and holders of an ESTA, no guarantee is given to pass through the border police. Ultimately, the immigration officer at the board decides whether entry into the USA is granted.