Legally speaking, Bank of China is Bank of China, one of the four largest banks in China. Banks buy rubles through formal and legal channels with the permission of the state. Nowadays, with the rapid development of world economic integration, sometimes it is not necessary to use foreign exchange when going abroad. With our country's money. Now, there are also foreign exchange purchases for storage. Now you can do it on mobile banking. Due to the continuous development of the country, it can be purchased by mobile phone, which is called foreign exchange purchase and settlement.