The first two methods listed here will duplicate both the artboard and its contents. Duplicating an artboard will allow you to copy the artboard as well as all of the text and object layers within it, making it easy to experiment with multiple design variations. However, they can be very helpful for some projects and are a great way to manage multiple designs within a single Photoshop project file.
Unlike Illustrator, artboards are not the default document type in Photoshop. Need to duplicate an artboard inside Photoshop? Need to duplicate an artboard inside Photoshop?.