For U.S. citizens, a valid passport is required to travel to China. The passport must be valid for at least siz months and have one blank page for the VISA. If you do not have a passport or need to renew your passport, visit the U.S. Department of State website for details.
U.S. -- A VISA is required for U.S. citizens entering China. According to the U.S. Department of State, "A U.S. citizen arriving without a valid passport and the appropriate Chinese VISA will not be permitted to enter China and will be subject to a fine and immediate deportation at the traveler's expense." The typ of VISA required depends on the purpose of your visit. There are various types of VISAs including business, tourist, student, among others. You must also choose the number of entries you will make into the country: single entry, double entry, or multiple entries. Select the appropriate VISA for your travel purposes.
Singapore/Brunai/Japan -- A citizen of Singapore, Brunei or Japan with an ordinary passport is exempted from a visa if he or she visits China's mainland for tourism, business, or meeting with friends or relatives, and if he or she enters China through ports open to foreigners, and stays for no more than 15 days. However, a visa is required for citizen of these three countries under any of the following circumstances: (1) An ordinary passport holder visits China for tourism, business, or meeting with friends or relatives, and stays for more than 15 days; (2) An ordinary passport holder visits China for the purpose of study, work, permanent residency, official visits or news coverage; (3) A Japanese citizen travels with a diplomatic or official passport. Information found: https://www.visaforchina.org/SGP_EN/generalinformation/visaknowledge/258911.shtml