This tool is called STAMP TOOL in Abode Photoshop. The cloning in Abode Photoshop provides us the facility to copy the pixels from another location. For example, We can use the pixels of the persons face to copy them to another part of the body.

The clone tool (stamp tool) is a handy way to remove some bad marks of pictures, to remove text from the images or remove an object from the picture without disturbing the background. To use this tool, we need to select it from the main tool box or by press S.

First of all we need to specify the area from where we want to get the pixels. Now, press ALT key and click the on the specific pixels of the picture. The source pixel's starting area is selected. Now, you have to paint these pixels to other location. While painting you can see the two mouse icons working at the same time. A + sign shows the source location and a circle shows the target location. We can change the properties of this circle. When this Stamp tool (clone tool) is selected, double click on the stamp icon in the properties tool bar. And select the size of the tool, hardness and its spacing.

 Cloning is commonly used in photo restoration, removing blemishes or correcting imperfections. You can also use it in blending images, removing people/objects from photos and adding people/objects to photos.

As stated above you would choose a clean area of the photo with like pixels/tones in one area and while the stamp tool is selected hit Alt to set the point you wish to clone. You would be cloning over an imperfect area for example to fix facial imperfections or to remove blemishes.

Depending on what you were doing you have to adjust the OPACITY and the FLOW along with your brush size, brush hardness and master diameter. Its kind of like a paint brush.

Always open a picture and duplicate it by right clicking on top of image and click duplicate. Close original image and work with the duplicate. Practice makes perfect and it does get easier in time.