An HTML Widget is a small computer program that runs in a browser. A widget can be available as an *.wdgt or an *.html file.
https://docs.bloomlibrary.org/html5-widgets/ provides more information about widgets.
If you are set up with a Bloom Enterprise subscription, here are things you can do:
For other existing pages, use the Bloom Change Layout controls to add a box that can hold an HTML Widget. Then, choose one for that box.
About the Change Layout controls
https://atomisystems.com/activepresenter/
https://en.wikipedia.org/wiki/Web_widget
https://blog.kotobee.com/book-widgets-everything-you-need-to-know/