The surname Wang can be replaced by "Wang" in English. There is no difference between Wang and Wong. They both have the surname Wang, but they are used in different regions.
Wong, the surname Wang (which has the same pronunciation as other Cantonese surnames such as Huang and Wang), is the English translation in the Hong Kong Government's Cantonese spelling of Chinese surnames. This way of writing is generally used in areas where Cantonese is the first language, and is distributed in Hong Kong, Macau and Guangdong, China, as well as overseas Cantonese-speaking areas.
Wong is spelled like Faye Wong, Wong Lo Kat, Wong Kar-wai, one of the four famous Chinese directors, etc.
Extended information:
The surname Wang is the largest surname in China (according to data released by the Public Security Bureau of the Ministry of Public Security). It is one of the three largest surnames in the world and the oldest in China. One of the surnames, ranking 8th in "Hundred Family Surnames".
The new version of "Hundred Family Surnames" was announced. Wang became the most common surname in China, with Li and Zhang ranked second and third. Morning News (Reporter Bai Minghui) Yesterday, the Ministry of Public Security announced the latest list of hundreds of surnames in my country. Ranking, Wang, Li, and Zhang are the top three, and their total population has reached 270 million, which is close to the total population of the United States.
Reference: Baidu Encyclopedia——wong