If I’m not misunderstanding the question, after selecting an area of an image you can press Ctrl + X. This will completely extract the selected area from the image to clipboard memory. If you then press Ctrl + V, this will paste the selected area on its own new layer where it can be manipulated at will without disturbing the surrounding image area. If instead of pressing Ctrl + X you press Ctrl + C then the selected area will merely be copied to clipboard memory unaffecting the original. Then pressing Ctrl + V will paste a copy of the selected area on its own new layer. On the other hand, if you have selected an area of an image and you just press Ctrl + J, this will automatically copy the selected area unto its own new layer as well saving you the extra step.