What is the first step in exposing web services for client applications in Salesforce?

The first step in exposing web services for client applications in Salesforce is to create a global class. A global class allows the methods within it to be accessed by external applications and other organizations. This is essential because web services in Salesforce must be defined in classes that are publicly accessible to fulfill the requirement of integration with external clients.

When defining a web service, making the class global is key as it ensures that the methods within can be invoked from outside the Salesforce organization. This means that client applications, which are intended to communicate with the Salesforce instance, can seamlessly call the exposed web service methods.

The process can continue with subsequent steps, such as defining the methods with the appropriate web service annotations and possibly generating the WSDL, but without first creating the global class, the web service exposure cannot take place. Thus, establishing a global class forms the foundational step in preparing Salesforce for web service interactions.