As you add layers to an image, it’s helpful to give them names that reflect their content. Descriptive names make layers easy to identify in the palette.
Double-click the layer name or group name in the Layers palette, and enter a new name.
Press Alt (Windows) or Option (Mac OS), and double-click the layer (not its name or thumbnail) in the Layers palette. Enter a new name in the Name text box, and click OK.
Select a layer or group, and choose Layer Properties or Group Properties from the Layers menu or the Layers palette menu. Enter a new name in the Name text box, and click OK.