The ESTA travel document can be applied for online. The applicant must enter some personal information and answer some questions about the applicant’s health and reasons for travel. The personal information requested includes age, sex, passport details, address and place of work and any previous convictions. You need a working internet connection as well as a valid passport and credit card in order to be able to successfully submit an application.
It is not possible to apply for an ESTA offline. The government website https://esta.cbp.dhs.gov/esta/ needs to be online and useable in order to apply for ESTA. If you can’t connect to the Internet, ask a third person you trust to fill out the application for you. If this is not possible, you can still apply for a regular visa, but you must visit the nearest U.S. embassy to do so.