White Balance is a function that removes unrealistic colours in photographs, so what you see matches the colours you get when you take the photograph. The filters of White Balance uses warm and cool filters, helping you to get the perfect colours in your photos.
These are the different pre-sets of White Balance, these vary in temperatures from warm to cool to help you get the perfect photo under the correct environment, these vary from things like Daylight to Cloudy to Fluorescent, you should be careful when using these, as a photo can show up really warm or really cool if set on the wrong White Balance setting that doesn't suit your environment.