The Visa Waiver Program is an initiative by the US Government that allows nationals from countries participating in the VWP scheme to travel on business or leisure into the USA without needing to obtain a Visa. Not everyone is able to enter the USA under the VWP program; you must be a citizen from one of the countries within the program in order to apply. If you are not from one of the partaking countries you need to obtain a B-1 or B-2 Visitor Visa in advance of your trip.
The advantage of entering the USA with an approved ESTA is being able to travel at short notice but the application must be made in advance with at least 72 hours prior to travel whereas the I-84 form is normally completed while flying to the United States or prior to entering a US port of disembarkation.
When applying for your ESTA you will be required to provide the following personal information for your application: first and surname, gender, date of birth, passport number, and passport country of issue, passport expiry date and country of citizenship. You are also able to give details on your travel destination, hotel or other address of stay and your flight number. During the application process, you will be expected to answer questions of eligibility such as whether you hold any previous criminal convictions and arrests, whether you have or have had contagious or communicable diseases and disclose any information of deportation or had your Visa revoked in the past.
Should your ESTA travel application be rejected you are still able to apply for a non-immigrant Visa to enter the USA. However, you are not able to enter the United States under the Visa Waiver Program. If you have been rejected via the VWP then you can apply for your Visa at the US Consulate or US Embassy before embarking on your trip.
With referencing to stopping over or entering the USA in transit while awaiting a connection you will still require authorization to do so which means that whatever your traveling circumstances if you enter American soil you will need an ESTA or Visa to do so. While applying for your ESTA you should fill in “In Transit” in the Address While in the United States field as well as clearly stating your final travel destination.