All individuals who wish to travel to the United States for a short period of time (up to 90 days) and who are citizens of any of the Visa Waiver Countries must apply by registering through the ESTA form.
If a traveler is planning to transit through the United States en route to another country, an authorization ESTA is still required.
Eligible children are also required to apply for an ESTA, regardless of their age. Parents or legal guardians may complete the ESTA application form on behalf of their dependent children.
If a traveler’s passport expires or is lost, stolen, or damaged and must be replaced, they will have to apply for a new ESTA with the new passport.
Note that the number of trips to the US does not relate to the ESTA validity – travelers can make multiple trips, without having to apply for a new ESTA after each one.
Green Card holders (permanent residents of the US) are not required to apply for ESTA.