If you are engaged in import and export trade, you must first obtain the foreign trade qualification in the Bureau of Commerce, then apply for the operator's license in the customs, and then get the verification form from the Administration of Foreign Exchange. After the transaction is completed, it will be written off at the "electronic port" of the customs and the foreign exchange bureau.
If there is trade in services, there is no quota restriction. For details, you can ask the local foreign exchange administration department or visit the website of the State Administration of Foreign Exchange.