In many parts of the world, it's easy to transfer money across international borders. For instance, the European Union's so-called "currency union" permits consumers and businesspeople alike to transfer euro-denominated sums between any of the union's member countries. Transfers from Lisbon to Berlin may occur just as often as transfers from Rome to Milan.
Currency transfers may be nearly as easy even in the absence of such currency unions. For instance, money can be transferred nearly instantaneously between the United States and dozens of other countries around the world. Many immigrants who work in the United States and Canada send a portion of their earnings to relatives who remain in their home countries. These individuals typically use money-transfer services like Western Union, MoneyGram and others to transfer these funds safely and effectively.
It's important to note that these transfer services are not identical to the "wire transfer" services that many banks employ. Whereas Western Union and other such outfits typically require individuals to procure hard cash before agreeing to make a transfer, the banks that perform wire transfers can do so using electronically-deposited funds.
It's also important to note that international money transfers between the United States and other countries are made easier by the fact that they're denominated in dollars. Since many international businesses and banks regularly accept dollar-denominated deposits, it's not difficult to find willing international recipients for such funds. The same is true with certain other currencies, including the euro and yen.
On the other hand, money transfers between countries that lack strong currencies may be far more difficult. While the Indian rupee is heavily used on a regional basis, it lacks international heft and is rarely used outside of its home country. As such, businesses that are based in other countries have little incentive to accept it during the course of a money transfer. Anyone who wishes to send a sum of money from India to China may have to convert it into yuan before doing so. Such a conversion can be performed by a street-corner currency-changing service.
Certain Chinese laws and customs may make it difficult to transfer large sums of money into the country. If the transfer involves the equivalent of several thousand dollars or more, it may be difficult to execute. To complete a large money transfer, the individual who sends the money may need to "park" it in an international bank account before wiring it to an institution on the Chinese mainland.