In China there are three mobile providers, China Mobile, China Unicom, and China Telecom. China Mobile and China Unicom are GSM providers while China Telecom is a CDMA provider. You can bring your own phone as long as it’s a GSM unlocked phone. Unlocked is NOT the same thing as off contract, you can call your current provider to give you an unlock code or Google for alternative methods. If you don’t bring your own phone, it’s fine. You can choose a new phone just like in western countries. Popular smartphone manufacturers include Apple, Samsung, Xiaomi, HTC, and Huawei. Also, when you by a phone, it’s not billed across your monthly bill, you pay for it up front. You can get a pretty nice phone for about 2,000 RMB or less, which is about $300USD.
If you go to a large branch of any provider there will almost always be an English speaking staff. Make sure to bring your passport with you when applying for a number or conducting any business on your account. Prepaid and contract options are both available for foreigners. There are multiple ways to pay your bill including going to a local branch, many convenience stores and pay in cash, you can purchase recharge cards from newsstands or convenience stores, or add money online with your bank account.