The immigration law office of Romben Law, APC in Los Angeles receives many inquiries from travellers from Visa Waiver Program (VWP) countries about the Electronic System for Travel Authorization (ESTA) program. The ESTA program is ONLY for citizens of countries who do NOT need actual visas to enter the USA. If you are a citizen of another country, you should not register with ESTA.
ESTA registration is for citizens of Visa Waiver countries who wish to enter the USA using the Visa Waiver. If the traveller is using another visa, such as F-1, H-1b, L-1, E-2, or any other nonimmigrant visa, ESTA registration is not required.
ESTA was put into place to allow the US Department of Homeland Security (DHS) to pre-screen travellers coming to the USA who are citizens of countries who do not need visas to enter the USA: the so-called Visa Waiver Countries. The entire application process is conducted online and operated by DHS.