Pega Platform includes an icon font set that you can add to your application's skin. You can then add icons from the system's icon font set to a control.
First identify the icon that you want to use:
Open the skin record and add the icon set to the skin, if you haven't already.
In the skin record, next to the py-icons row, click the Open icon to open the text file.
Scroll through the file until you find the name of the icon that you need.
Next, add the icon font to the control:
Open the section that contains the control and then open its Properties panel.
On the General tab, select Icon Class from the Image source drop-down list.
Enter the letters "pi", a space, and the name of the icon.
Submit the updated properties and save the section.
To see how the button is displayed on the form, select Preview in the control record's Actions menu.