Shadows give a real paper collage feel to your collage. Shadows generally have three components the X and Y offset that specify the location of light source and blur that specifies the distance of the light source.
Click the text to select it.
Go to Text tab on the top left of the appliction.
Check Draw Text Shadows.
Adjust the X Offset, Y Offset, and Blur sliders.
You can select text only if text is unlocked at the top of the application.