Hypnosis is a procedure during which a person experiences changes in sensations, perceptions, thoughts or behaviour.  The hypnotic context is generally established by an induction procedure.

Most common techniques that are used are suggestions for relaxation, calmness and well-being. Instructions to imagine or think about pleasant experiences are also commonly included in hypnotic inductions.

People respond to hypnosis in different ways. Some describe hypnosis as a normal state of focused attention, in which they feel very calm and relaxed. Regardless of how and to what degree they respond, most people describe the experience as very pleasant.
Some people are very responsive to hypnotic suggestions and others are less responsive.
A person’s ability to experience hypnotic suggestions can be inhibited by fears and concerns arising from some common misconceptions.

Contrary to some depictions of hypnosis in books, movies or television, people who are hypnotised do not lose control over their behaviour. They typically remain aware of who they are and where they are, and remember what transpired during hypnosis.
Hypnosis makes it easier for people to experience suggestions, but it does not force them to have these experiences.