Copying a Layer from One Document to Another
To copy a layer from one document to another, you need to make sure that you’re in Windowed display mode. You can switch display modes by pressing Command + M (Mac) or CTRL +M (Windows). Next, open both documents and set the document that contains the layer as the active document. Click the Layer Adjuster tool from the toolbox and choose the layer that you want to copy from the Layers panel. Drag the layer from the active document window to the other document window.