What is ESTA?
Citizens of the Visa Waiver Program countries do not need visa for traveling to the U.S.; instead, they have to receive an ESTA application approval.
ESTA is Electronic System for Travel Authorization, approval of which permits arriving at the U.S. in scope of the Visa Waiver Program. This system establishes traveller’s compliance for traveling to the U.S. ESTA system assesses if the candidate does not rise any risk to implementation and safety of the USA rights protection.
In case the ESTA approval is received, you are entitled to use an operator for arriving at the U.S. in the scope of the Visa Waiver Program.
If the traveller has a valid U.S. visa, he/she is entitled to arrive at the U.S. with the purpose of this visa; and, additional ESTA approval is not required.
Since 12 January 2009, the ESTA approval is a mandatory requirement to all citizens of the Visa Waiver Program countries for traveling to the U.S. If you have received the ESTA approval and plan to travel to the U.S. by air or sea, you do not have to fill in the green card I-94W.
The ESTA approval is valid for two (2) years or until expiration of the passport validity period. You are entitled to stay in the U.S. with a valid ESTA approval for up to ninety (90) days in one visit.