Can the expenses paid by Hong Kong companies to mainland companies be paid in advance by domestic bank cards of shareholders of Hong Kong companies?

Of course.

After consulting China Travel. Com, the main body of a Hong Kong company can entrust a mainland company to make an advance payment, but it needs a power of attorney from the mainland company, and it also involves some expenses, so it is generally impossible for the entrusted mainland company to provide services free of charge.

Hong Kong, referred to as Hong Kong for short, is the People's Republic of China (PRC) Special Administrative Region, located in the south of China and east of the Pearl River Estuary.