In order to enter the United States or even just to pass through an airport for flight changes, you need either a visa or a passport. The most convenient way to enter the United States is to take advantage of the Visa Waiver Program, which allows you to travel without a visa.
Before boarding any aircraft or ship en route to the United States, remember to apply for an electronic travel authorization, (ESTA - Electronic System for Travel Authorization)
I valid documents to enter the United States of America without the need for a visa with the "Visa Waiver Program", are the following:
Passport with machine-readable passport
Electronic passport with microchip inserted in the cover
To benefit from the Visa Waiver Program, the following are required requisitions:
-have a return ticket
stay in the United States no longer than 90 days
-travel exclusively for business or tourism
If one or more of these requirements are missing, it is necessary to apply for a visa. Staying in the United States beyond the allowed 90 days compromises the possibility of future travel to the country. To benefit from the Visa Waiver Program, children under 18 must have an individual passport.