If you use a version of Android 2.3 or below, click on the free space on the screen and hold a few seconds. A pop-up menu. Click on "Widgets / Widgets» and determine what kind of addition you want to see on the desktop, here and now.
If you are the proud owner of a smartphone or tablet running Android 4.0, your widgets are added to the desktop in a different way. It should go to the "Application Menu", select the tab where the "Widgets" (at the top), press and hold your finger on the widget that you want, and then simply drag it to the desktop.