The ESTA form is applied for online. The cheapest and safest way to get it is via the official ESTA form page of the U.S. Customs and Border Protection Authority.
It is not possible to print out the form for an ESTA application and submit it to any US authority. The application can only be done online. There are many commercial providers who can be commissioned to process an ESTA application. Such providers usually charge a higher fee than the authority itself. In rare cases, the customer also receives an added value, but as a rule it is more of a medium-heavy rip-off.
Make sure that you either submit the application to a professional provider who really provides you with added value for the extra charge, or complete the application on the authority’s website: https://esta.cbp.dhs.gov/esta/