In photography you have the two main settings: the shutter speed and the aperture. The shutter speed controls how much of the image has motion blur or how much is frozen however the aperture controls a thing called the depth of field. The depth of field is how much of a picture is in focus. With a shallow depth of field you can choose where to focus in order to blur the background. In order top achieve a shallow depth of field you need a low aperture like F4.5 or F5.6. Examples of a shallow depth of field can be seen here and here.
On the other hand a deep depth of field means the whole image is in focus. This is good for landscape shots. To get deep depth of fields you need high apertures like F26. Examples of a deep depth of field can be seen here and here.