To Hong Kong
Nationals of about 170 countries and territories may visit Hong Kong without a visa/entry permit for a period ranging from 7 days to 180 days. For more information, you may refer to the "Visit Visa / Entry Permit Requirements for the Hong Kong Special Administrative Region" webpage. There is a table at “Part II” in which you can see if you need to apply for a visa to come to Hong Kong.
To Mainland China
If you want to visit Mainland China after the conference, please go to the "China Travel Service Hong Kong" webpage to apply for a China Visa.