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Do I need any other documents apart from ESTA?

Yes. You may choose to print your valid ESTA authorisation (which is generally recommended, though not necessary unless your airline specifically request that you print it), but you will definitely need your passport to travel to the U.S., as the authorisation is centred around your passport number. This must be an electronic passport (ePassport) with a digital chip containing biometric information about the passport owner and that also has a machine readable zone on the biographic page. You can identify if you have a chip by checking if there is a small logo of a rectangle and a circle on the front of your passport, similar to this: 
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A machine readable passport is one that contains 2 lines of text on bottom of the information page of your passport. This text containing symbols and letters can be scanned by machines for information. If your passport does not have this feature and you’re part of a Visa Waiver Program Country, you would need to apply for a standard visa to visit the U.S..
The passport must also contain a digital photograph, that is one that is printed directly on to the data page.
If it is the case that you have changed your legal name or gender, you will need to bring legal proof of any identity change as well as proof showing you were the holder of the previous identity, if you have not managed to change your passport yet.
Once you land in the United States, you will also need to fill any required paperwork, such as customs declarations, which may be filled in at an Automated Passport Control (APC) Kiosk when you land. You will also need to prove border agents with information on your United States point of contact and where you will be staying in the U.S., along with the reasons for your journey to the U.S. (whether for business or pleasure), and the duration of your stay. Documents that support your answers to such questions may be useful, such as copy of return flight tickets (showing you will not be present for more than 90 days in the U.S., and that you are travelling with a commercial carrier), receipts and tickets for travel and accommodation, etc.