Can a Wide 21X Zoom nikon camera with a 14.4 megapix have different lenses?

I'd like to get into photography and it looks like I can change the lenses, but can I really?

Does this Nikon have a model number? Megapixel means nothing related to your question. 21X Zoom sounds like the Nikon L120 bridge camera. If that's the case your answer is NO!

You have not given the model number of your camera. So your question can't be replied.
However, from what you wrote it seems you have a compact camera. In that case, NO, its not possible to change lenses. Lenses can only be changed on a DSLR or a SLR camera.

http://www.soumennath.com

Your camera does not have an interchangeable lens mount. The lens is permanently attached to the camera. You can't change it.