DNA fingerprinting is used in many different ways for a variety of reasons. It can be used to study and potentially even cure diseases, to locate a relative or to prove that you are related, or to provide evidence if you committed a crime and left behind some DNA.
In order to do DNA fingerprinting, first you must collect a sample which can include blood, a hair, saliva, and even sweat. It is most commonly done with a blood test or by swabbing the inside of your cheeks. Then it is broken down chemically and dissolved in water. Once this is finished then they will take just a section of the DNA from the sample and study it.