Comments To link two or more layers, select them in the Layer’s panel and click the Link icon. You can also assign a custom keyboard shortcut using the Keyboard Shortcut Editor to ass a shortcut to Link/Unlink layers. When layers are linked together, commands applied to one layer will also be applied to linked layers (when possible). This includes, moving, transforming, aligning, distributing, apply styles, etc.
Note: before Photoshop had the ability to select multiple layers, linking was more heavily utilized. Now, it is used with complex documents when multiple layers require identical changes thereby eliminating the need to have to reselect multiple layers again and again.
