This has nothing to do with the telescope. It is a property of the eyepiece. The eyepiece presents to the eye an enlarged view of the field stop located in the eyepiece. This field stop is determined by the desired eyepiece field of view, the magnification of the eyepiece and the focal length of the eyepiece. It is limited only by the size of the mechanical tube holding it and of course the optical characteristics of the eyepiece.
Eyepieces come in a great variety of optical types.
They range from very simple Kellner eyepieces which have simple optics to highly complex super-wide types. With the wider type designs, the observer sees a very large apparent field of view. This can be quite impressive, but, it must be emphasized that this large field is only that of the field stop and is only indirectly related to the actual size of the star field observed. Let us start by looking at a typical set of eyepieces. Now the actual field of view of the telescope is determined only by the size of the field stop and the focal length of the telescope.