On webs site builder how do you insert a widget box widget?

There is no one thing called a widget. The term is used generically like gadget or gizmo. It's often used in an academic context, especially in business schools or economics classes. For example, an...

Yahoo! Widgets is the free application platform for Mac OS X and Microsoft Windows

you can go to safari, click Apple, and search widgets.

Widget is the pink bunny in Wow wow Wubbzy. She is Wubbzy's friend.

You need to have a code to use if you want to do that.