EVUS is an online Visa update system; it is not a Visa. It does not meet the legal requirements to serve as a US entry Visa when one is required. The EVUS is a mandatory requirement that should be completed before traveling to the United States.
All foreign nationals who visit the United States of America have an obligation to hold a valid entry Visa. Those who wish to travel to the U.S. for a short-term as a visitor must first obtain a nonimmigrant B1, B2 or a combined B1/B2 Visa category. The EVUS is electronically linked to a person’s passport and valid 10-year visa.
The Department of Homeland Security established the EVUS to automate and improve security. As of November 29, 2016 citizens of the People’s Republic of China, including citizens from Macau, Hong Kong, and Taiwan traveling on a People’s Republic of China passport, who hold a 10-year Visitors (B1, B2, B1/B2) Visa are required to apply for EVUS in addition to their current visa.
Bear in mind that if you arrive at any Us airport on a 10-year B1, B2 or a B1/B2 visa, without having enrolled with EVUS, your entry will be denied. It is strongly advised to enroll in EVUS at least 72 hours before departure. Each individual is assigned an enrollment number that can be used to check the status of the EVUS.
Those travellers whose final destination is not the United States but are in transit are also required to apply for the EVUS. The enrollment process can take up to 20 minutes to complete.
Note: Holders of any other visa class that is not B1, B2 or B1/B2, will not be required to apply for EVUS before traveling to the United States.