You can select one or more layers to work on them. For some activities, such as painting or making color and tonal adjustments, you can work on only one layer at a time. A single selected layer is called the active layer. The name of the active layer appears in the title bar of the document window.
For other activities, such as moving, aligning, transforming, or applying styles from the Styles panel, you can select and work on multiple layers at a time. You can select layers in the Layers panel or with the Move tool .
You can also link layers. Unlike multiple layers selected at the same time, linked layers stay linked when you change the selection in the Layers panel. See Link and unlink layers.