If you want users to initiate actions such as submitting data, executing a web service operation, or executing a database query, you can add a button to the form. With the help of LiveCycle Designer ES’s built-in support for client-server communications and scripting, forms can support these kinds of actions through buttons:
After you add a button object to the form design, you can edit the caption text and manipulate the object’s properties in the Field, Submit, and Execute tabs of the Object palette. You can define these properties:
LiveCycle Designer ES also includes four additional buttons that are preconfigured to provide specific functions. They include an email submit button, an HTTP submit button, a print button, and a reset button.
See also 

Overview of buttons