The nose cone is the foremost part of a rocket. In launch vehicles, nose cone contains the most vital part of the missions, i.e. the equipment, experiment, plants and animals. Usually during satellite launches, the nose cone becomes the satellite on reaching the exosphere.
In model rockets, the nose cone serves a basic purpose of sustaining the aerodynamic loads. It can also contain the avionics if the rocket is equipped with an avionics system.
[Source: rocketryforum.com]
There are many shapes of nose cones. The most efficient ones are conical and ogive. Other shapes like parabolic, elliptical, power series and haack series shapes depend upon the mathematical parameters, but overall have almost similar appearance and results. The materials used for the nose cone are balsa, foam sheet, or usually 3d printing materials. It should be strong enough to withstand the aerodynamic loads and prevent buckling on touchdown.
[Source: rocketryforum.com]
The nose cone is connected to the body tube using shock cord and a screw eye, and thus during descent, the parts remain intact, attached to the parachute via the shock cord.