A more thorough explanation:

The Visa Waiver Program (VWP) allows citizens or nationals of participating countries to travel to the United States for tourism or business for stays of 90 days or less without obtaining a visa. To be eligible for the program, travelers must meet certain requirements and obtain approval for travel authorizations through the Electronic System for Travel Authorization (ESTA) before traveling without visas. Even if their visas are waived, they still need to possess passports during traveling.

To be eligible for the Visa Waiver Program, travelers must confirm that their travel purpose is for tourism or business, such as professional conferences, business conventions, or vacations, for no more than 90 days. Citizens or nationals of the following countries or regions are eligible for the program:

• Andorra
• Australia
• Austria
• Belgium
• Brunei
• Chile
• Croatia
• Czech Republic
• Denmark
• Estonia
• Finland
• France
• Germany
• Greece
• Hungary
• Iceland
• Ireland
• Italy
• Japan
• Latvia
• Liechtenstein
• Lithuania
• Luxembourg
• Republic of Malta
• Monaco
• Netherlands
• New Zealand
• Norway
• Poland
• Portugal
• San Marino
• Singapore
• Slovakia
• Slovenia
• South Korea
• Spain
• Sweden
• Switzerland
• Taiwan*
• United Kingdom

If travelers from the above countries already have B visas, they should not apply for any visa waiver, as they can use B visas to travel to the U.S.

U.S. Customs and Border Protection (CBP) operates the web-based system, ESTA, to determine the eligibility of travelers to enter the U.S. ESTA authorizations are usually valid for two years. During this period, if a traveler gets a new passport, changes their name, gender, or citizenship, or has any changes relating to ESTA application questions, they should update ESTA.

Passports should be valid for more than 6 months after the planned departure from the U.S.

1. Answer Disclaimers
2. Enter applicant, personal, and travel information
3. Answer eligibility questions
4. Review application
5. Pay $14 application fee

Travelers are not allowed to extend their stay in the U.S beyond the initial admission period. Travelers are not permitted to change their status in the U.S.

An Australian citizen who wants to visit the U.S. for a two-week vacation can apply for travel authorization through ESTA instead of applying for a visitor visa. If approved, they can travel to the U.S. without a visa and stay for up to 90 days.

A French national who wants to attend a business conference in the U.S. can also apply for travel authorization through ESTA. If approved, they can travel to the U.S. without a visa and attend the conference for up to 90 days.

These examples illustrate how citizens or nationals of participating countries can travel to the U.S. for tourism or business without obtaining a visa through the Visa Waiver Program, as long as they meet the program's requirements and obtain approval for travel authorizations through ESTA.

*According to the Taiwan Relations Act of 1979, “all references to country or countries in the Visa Waiver Program authorizing legislation are read to include Taiwan. This is consistent with the United States' one-China policy, under which the United States has maintained unofficial relations with Taiwan since 1979.”