For non-Chinese travelers, cash is king (still) in China. Locals now use AliPay or WeChat Pay for pretty much all of their day-to-day transactions as these are the 2 dominant mobile payment platforms in China accepted by big brands as well as street vendors. However, in order to use these payment apps you need to have a Chinese bank account. You're not going to have a Chinese bank account as a traveler.
I've heard rumors that you can now link your Visa or Mastercard to AliPay and WeChat Pay and these apps without having a Chinese bank account, but I tried and have yet to make it work personally, as of July 2019. If you have been able to do that I'd love to know how you did it
If you really want to use these apps, you can find a friend with Chinese bank account. Give him/her cash, and then have him/her give you "red pocket" through these apps (essentially in-app money transfer) to your WeChat/AliPay account
International credit card acceptance is fairly generally but still accepted in many places in tier 1 cities like Shanghai. It's limited to airlines, major hotels (all international brands and big domestic brands), and semi upscale chain restaurants in malls in the major cities (mainly Shanghai and Shenzhen, and to a lesser degree Beijing and Guangzhou)
By credit cards I mean Visa and MasterCard. AMEX has almost 0 acceptance outside of international hotel chains
Discover, Diners Club, JCB, and other cards I think most likely has 0 acceptance rate
UnionPay is the domestic credit card brand, but I doubt you'll carry one of these
Despite what you may have read about the death of cash in China, it's still accepted everywhere and the government recently made another announcement reinforcing businesses to accept cash.
My recommendation is, carry enough cash with you when you're in China as it is accepted everywhere (and carry lots of small bills like 5RMB, 10RMB, and 20RMB for public transit). But bring a Visa or MasterCard and use it wherever you possible can (like hotels) to save cash
