Almost all travelers have to obtain a visa from a Chinese embassies and consulates, and through authorized tour operators and visa agents, before to enter the People's Republic of China. Hong Kong and Macau issue their own visas, which are easier to obtain and have longer duration.
Tourist visas must usually be used within six months after it was issued. They are normally valid for 30 days from the time of your entry into the country, but in Hong Kong and Macau you can often get a 3 month visa.  To apply for a tourist visa you must submit an application form, two passport-size photographs, and your passport in effect for at least six months more, and pay the corresponding fee. Sometimes may be asked for a copy of any air tickets, hotel bookings, and the reason of your trip or your profession occupation.