Hi!
Assuming you developed your web service client in Java or some other language that runs on a JVM, then the program containing the web service client must be deployed on a computer that contains a JVM.
The most common is to deploy to a web container, such as
Tomcat or GlassFish. Since you mention HTML, I assume your program is a web application that will produce HTML.
If your web service client is indeed a part of a web application, then it must be invoked by some part of the application, perhaps by a controller (C in the MVC
pattern).
Best wishes!