A simple magnifying glass is one type of converging lens or convex lens.
If we keep an object between the focus and the center of the lens, then the produced image is many times larger than the object's actual size.
A convex lens of small focal length is an ideal lens to make a magnifying glass.
Magnifying glasses get an enlarged image of a nearby object. So making use of one with a larger focal length is not applicable, so we need to place it at a larger distance. So these magnifying glasses with smaller focal lengths are preferred.
Image formation on a magnifying glass
Therefore, a simple magnifying glass consists of a convex lens of a small focal length.
