The Myers–Briggs Type Indicator (MBTI) is created from the conceptual theory proposed by Swiss psychiatrist Carl Jung. He speculated that people experience the world using four principal psychological functions—sensation, intuition, feeling, and thinking—and that one of these four functions is dominant for a person most of the time. Each person is said to have one preferred quality from each category, producing 16 unique types. The underlying assumption of the MBTI is that we all have specific preferences in the way we view our experiences, and these preferences underlie our interests, needs, values, and motivation. Both Myers and Briggs were fascinated by Jung's theory of psychological types and recognized that the theory could have real-world applications. During World War II, they began researching and developing an indicator that could be utilized to help understand individual differences. Myers created the first pen-and-pencil version of the inventory during the 1940s, and the two women began testing the assessment on friends and family. They continued to fully develop the instrument over the next two decades. No one personality type is "best" or "better" than another. Taking the MBTI test can help you learn more about yourself and even give you realizations about your purpose. 

INTROVERSION (I) EXTRAVERSION (E)
Jung believed that for every person, each of the parts is expressed mainly in either an introverted or extraverted form. Introversion is the state of being predominantly interested in one's own mental self. Introverts are typically perceived as more reserved or reflective. The introvert is more comfortable with the inner world of thoughts and feelings, so they will see the world in terms of how it affects them. Introverts are more comfortable living alone and being by themselves. Introverts are "inward-turning" and tend to be thought-oriented, enjoy deep and meaningful social interactions, and feel recharged after spending time alone. Extraverts are "outward-turning" and tend to be action-oriented, enjoy more frequent social interaction, and feel energized after spending time with other people. Extroverts are actively involved in the world of people and things; they are socially active and more aware of what is going on around them. The idea of being alone terrifies them, leaving them alienated from their inner selves. We all exhibit extraversion and introversion to some degree, but most of us tend to lean to one side more. 

SENSING (S) INTUITION (N) 
Sensing means that a person mainly believes in the information they receive directly from the external world. Sensing types prefer the known, the factual, the actual, the concrete. Intuition means that a person believes mainly information they receive from the internal or imaginative world. Intuition is not mere perception or vision, but an active, creative process that puts into the object just as much as it takes out. People with heightened intuition enjoy thinking about possibilities, imagining the future, and abstract theories. 

THINKING (T) FEELING (F)
People who prefer thinking place a greater emphasis on facts and objective data. They tend to be consistent, logical, and impersonal when weighing a decision. Those who prefer feeling are more likely to consider people and emotions when arriving at a conclusion. Feeling is an affective, sentimental function. It involves judging the value of things or having an opinion about them on the basis of our likes and dislikes. Thinking, in contrast to feeling, focuses on what things simply are, whether or not they are likable. 

JUDGING (J) PERCEIVING (P)
Those who lean toward judging prefer structure and firm decisions. People with the Judging preference want things to be neat, orderly, and established. People who lean toward perceiving are more open, flexible, and adaptable. The Perceiving preference wants things to be flexible and spontaneous. Perceivers want things open-ended.

These are the 16 types listed below:
ISTJ (the inspector)
ISTP (the crafter)
ISFJ (the protector)
ISFP (the artist)
INFJ (the advocate)
INFP (the mediator) 
INTJ (the architect)
INTP (the thinker)
ESTP (the persuader)
ESTJ (the director)
ESFP (the performer)
ESFJ (the caregiver)
ENFP (the champion)
ENFJ (the giver)
ENTP (the debator)
ENTJ (the commander)