You can use the Aperture of the Camera to control how much is in focus. The higher the Aperture the longer the depth of field and the more that is in focus closer to and further away than the object you are focused on.

Low or short depth of field

Only the hand that the camera lens is focused on is in focus. Everything firther away is out of focus. This photograph is taken using a low aperture 

classic portrait photograph where the person is in focus and the less important background is out of focus

These three photographs use a low depth of field and a low aperture to draw the viewers attention to one element of the photograph

These two photographs use a low aperture but the person focused on is far away so that the foreground and the background are both out of focus

It is harder to find examples of work of high aperture photography on the internet. It is easier to find examples of people using a low aperture to push things out of focus. The image above found using a google search shows the different between a low aperture ( f2.8 on the left) and a higher aperture (f16) on the right. It shows how changing the aperture changes the photograph