Hong Kong’s corporate taxes are already very low compared to most western countries. On top of that, these already low corporate taxes only apply to profits earned locally in Hong Kong. So if you operate a store there, or an office where you do business, or at least sign relevant contracts for your business on Hong Kong soil, then you’re going to pay the regular corporate tax in Hong Kong. If, on the other hand, you never work in Hong Kong, and maybe only come over to pick up the mail and do some shopping, and your clients are located outside Hong Kong as well, chances are your profits fall into the offshore category.
And those offshore profits are tax free in Hong Kong.
All you have to do is inform the accountants that you intend to apply for this tax exemption, and tell them which of your profits you think are offshore profits (and which not, if any). They will take care of the rest and mark the corresponding earnings accordingly in the financial report. If this is the first time you apply for the exemption, the IRD will get back to you at some point with some paper work to fill out before they finally grant (or not) the offshore tax exemption status.
It is important to keep in mind that this whole ‘offshore tax free’ thing is just about the Hong Kong corporate tax. You are still liable for personal income tax in Hong Kong (for your director’s salary, if you pay yourself one) and, depending on your citizenship and residency status, personal taxes on salaries and other earnings (i.e., dividends) of any other countries you have to do with in one way or the other.