Visit Visa (Training)

Hi,

I'm currently resides in Sri Lanka and recently I've got a Job offer from a Chinese company. At the moment they are in the process of preparing my working Z. However I have to visit China on 24th for some project orientation and after that training in Hong Kong where the company is registered in both territorials.

If they provide ticket confirmation, hotel reservation and invitation letters, what would be the procedure to get it for both countries and do I need invitation for both countries separately? How long it will take?