If you are interested in traveling to the USA for a vacation and you live in a country that is a part of the Visa Waiver Program then you will need to apply for an ESTA. The ESTA USA is a form of electronic authorisation which pre-verifies that you are eligible to travel to the United States. It replaces the forms that people used to have to fill out while on the aircraft.
You can apply for the ESTA via the official government website, and it is quite a simple process. There is a nominal fee, but the ESTA is valid for more than one trip to the USA so it is not expensive when that is taken into account. Most people have their ESTA verified within minutes – but it is worth applying well in advance, and before booking any flights, just in case there are delays in processing the application.
There may be a delay if there is any difficulty in confirming your identity or if there are any issues such as a case of mistaken identity.
There are third party services which try to sell people the service of filling out the ESTA form, but these are a waste of money and could actually delay the process if there are any issues with the application. There is no need to pay anyone else to do the form for you – if you have access to the Internet then simply complete the form yourself, and use your own email address so that you can get a response as quickly as possible.
If you are travelling for business then you should check whether or not you would need a full Visa for your journey. Contact the USA Embassy for advice, so that you do not get denied entry for travelling on the wrong papers.