A traveller who, on the day on which the traveller boarded a specified aircraft, or during the 21 days before that day, has stayed in any countries outside China* (excluding very high-risk places specified otherwise), must provide confirmation in English or Chinese of room reservation in a hotel in Hong Kong for not less than 21 nights starting on the day of the arrival in Hong Kong of the relevant traveller from the rest of the world.
◊The List of Designated Hotels >> https://www.coronavirus.gov.hk/pdf/designated-hotel-list_en.pdf
**high-risk specified place (i.e. Bangladesh, Belgium, Canada (starting from 25 December), Ecuador, Ethiopia, France, Germany, India, Indonesia, Kazakhstan, Nepal, Pakistan, the Philippines, Romania, Russia, South Africa, Turkey, Ukraine, the United Kingdom and the United States of America), must provide the another documents . >> Specified conditions imposed on inbound travellers who have visited specified high risk places