Visa requirements are different according to each country. Visitors to Hong Kong must hold a passport that is valid for at least six months beyond the planned departure date to Hong Kong. Visitors from most countries are not required to obtain visas and can stay for periods varying from 7 days to 180 days, depending on nationality.
Please check the web site of the Hong Kong Immigration Department and the Chinese embassy or consulate to find out whether you need to apply for an entry visa to Hong Kong. Please check with the Chinese embassy or consulate early as the application of some nationalities may not be done at the Chinese embassy or consulate and please contact if you have any problem. More information about the visa policy of Hong Kong can be found here.
During the registration process, you may request an electronic invitation letter for free or a hardcopy invitation letter with original signature at a cost.