Only RMB (Yuan Dollars) is acceptable in Shanghai when you do shopping. Foreign currency and traveler's cheque exchange is available in most of China's cities. Banks, hotels, airports, even the shopping malls will provide such service. In some of the places, the self-service facilities are also equipped to cope with overseas tourists. You can check the Currency Converter(https://www.travelchinaguide.com/tour/currency-converter.htm) to find the details in this web.