We all drift in and out of Hypnosis every day, it is a natural state of human consciousness, often compared with daydreaming. During Hypnosis you are fully conscious, but have phased out what is happening around you, whilst concentrating on your own thoughts or suggestions by the hypnotherapist.
Consider a of time you have driven home from somewhere, you had been aware of what you were doing, driven safely etc. but do not remember passing the regular landmarks on route. Perhaps you were even so absorb, that at the end of journey you wonder how you got there at all! This is a form of hypnosis, you were focused on the process.
Hypnotherapy is where you are guided in to trance by a professional hypnotherapist using various techniques for therapeutic purpose.
It is important to note that you cannot be hypnotised if you do not wish to be hypnotised & no one can make you do things that are compromise your values and morals.