Now ESTA became compulsory 12 January 2009. VWP visitor are required to complete a Customs declaration upon visit in the U.S. whether or not they have an ESTA authorization. VWP visitors are no longer required to complete the green card.
ESTA is an online system application program which is related to the Visa Waiver Countries for touring work and transit medical purpose. ESTA Travel authorization are valid for 2 years. When travel to the US with an ESTA Travel Authorization you must stay for a maximum of 90 days.
How long is my travel authorization valid?
Travel authorizations are mainly valid for two years or until your passport expires and a visitor may travel to the U.S territory repeatedly within the validity period without having to apply for another ESTA Visa.
ESTA approval authorizes a traveler to board a carrier for travel to the United States under the VWP.
While recommends that you apply at least 72 hours before travel, you may Apply ESTA any time prior to boarding.
In most cases, a response is received within seconds of submitting an application form.
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