The first way: you can carry your ID card to state-owned banks [such as Bank of China, Bank of Communications, etc.] or joint-stock banks [such as China Merchants Bank, Everbright Bank, etc.] or foreign banks [HSBC Bank, Citibank, etc.] can directly change foreign currencies into Renminbi (professional language is business).
The second way: you can exchange foreign currencies into RMB at foreign exchange shops, such as airports or exchange points in some first-tier cities. The handling method is similar to bank exchange settlement business. You need to carry valid certificates and complete the exchange business within the quota under your name.
Supplementary note :(1) at present, the first method and the second method do not accept foreign currency coin exchange service, only banknote exchange service.
(2) The foreign exchange quota is only applicable to the exchange between foreign currency and RMB. If foreign currency is exchanged for foreign currency, it is not subject to the external management quota.