I am indian citizen, can you advise how do I get a 12 month or more duration multiple entry visa?

Hi, what kind of business purpose you will focus in HK? You will go to do business, join one or just for a business visit to companies?
In general, you need to prepare your valid passport, an application form with a recent taken photo, round trip tickets to Hk, an invitation letter from HK and your bank statement. If you want to have a multiple type, you need to provide your detail plannings to prove the necessity of a multiple one, so that they will issue you the suitable one based on your requirements.