In Sitefinity, widgets are used to display your content on all of your webpages. Any content you want to be displayed, must be done with a widget. This means that regardless of the type of content, site builders will have to use a related widget to display it on their webpages.
Each widget is designed to display specific pieces of content. As a site builder, you will choose the widget you are going to use based off your content. For example, if you want to display an image, you will choose an image widget.
Widgets often have template properties that allow you to choose how you want your content displayed, as well. For example, a call to action widget is a clickable button. Some of the available properties allow you to change the button color and the size of button.
To use widgets, you simply drop them on the page in edit mode and click Edit to add content and configure the display.
There are a many widgets you can use in Sitefinity. You can use a combination of different widgets and widget properties to further customize the design of your webpage. Each widget has it's own webpage to describe what it does and how to use it. Find the widget that suits your needs!