Who Needs a Visa to Visit Hong Kong
Nationals of about 170 countries and territories may visit Hong Kong without a visa, and can stay for periods varying from 7 days to 180 days depending on nationality.
Nationals of the US, Europe, Australia, Canada and New Zealand don't require a visa to enter Hong Kong for stays of 90 days, 180 days for UK nationals.
Nationals of Albania, Armenia, Cambodia, etc. require a visa to enter Hong Kong.
All visitors to Hong Kong must have a passport that is valid for at least one month to six months (depending on nationality) after the period of their intended stay in Hong Kong.
If you want to travel from Hong Kong to China mainland, you may need to apply for a China visa.
Please visit the website for more details: https://www.gov.hk/en/nonresidents/visarequire/general/index.htm