Layer styles let you quickly apply effects to an entire layer. In the Effects palette, you can view a variety of predefined layer styles and apply a style with just a click of the mouse.
The boundaries of the effect are automatically updated when you edit that layer. For example, if you apply a drop shadow style to a text layer, the shadow changes automatically when you edit the text.
Layer styles are cumulative, which means that you can create a complex effect by applying multiple styles to a layer. You can apply one style from each style library per layer. You can also change a layer’s style settings to adjust the final result.
When you apply a style to a layer, a starburst icon appears
to the right of the layer’s name in the Layers palette. Layer styles
are linked to the layer contents. When you move or edit the contents
of the layer, the effects are modified correspondingly.
Once you choose Layer > Layer Style > Style Settings, you can edit the settings of a layer’s style or apply other style settings or attributes available in the dialog box.