There are four different ways in which services can be delivered internationally, depending on the locations of the supplier and the customer:
Cross-border trade. Both supplier and customer are in their own countries, while the service crosses the border. For example, services like consulting can be provided by phone or over the internet.
Consumption overseas. The customer visits the supplier's country, where the supplier provides the service. For example, international travel and tourism services can be provided in this way.
Setting up overseas. The supplier establishes a presence in the customer's country. For example, a law firm or financial services provider might open a branch office overseas.
Movement of individuals. Individuals who will provide the service travel to the customer's country. For example, an architect might travel overseas to work on designing a building there.
The above methods of service delivery are defined in the World Trade Organisation's General Agreement on Trade in Services (GATS).
Read more about the legal issues for international trade in services.
The way the services are supplied has important implications for which country's laws and taxes apply. For example, if you travel to another country to supply a service, you might be liable to pay local taxes on your earnings there.
If you are a service supplier, you should take care to ensure that you do not accidentally supply your service overseas. For example, if you offer financial services on your website, it might be seen in countries where this is illegal without a licence.