Photoshop/101basics/The Basics/Workspace/menubar/layer/layers effects/coloroverlay

=> Photoshop Tutorials => Photoshop 101 - The Basics 
=> Photoshop Layers Basics ==> Layers Style Effects ==> Color Overlay Effect

Color Overlay Effect

Blend Mode

Color  : You can change the color by clicking on this square and then choosing the desired color

Opacity  : This would determine the density of the color.

Preview : This would give you a preview of how the Color Overlay effect is applied.

A sample of the color overlay effect:

The Original layer & A layer with the color overlay effect (Blue Color)