Psychological type is a concept developed by Swiss psychologist Carl Jung (1875–1961), who described different patterns of normal behavior resulting from people’s inherent tendency to use their minds in different ways. Your psychological type, also called “personality type,” is the pattern of behavior you tend to show.
In the Myers-Briggs Type Indicator assessment, your type is indicated by your preferences between Extraversion or Introversion, Sensing or Intuition, Thinking or Feeling, and Judging or Perceiving. Your four preferences combine to form one of 16 distinct personality types, each of which is denoted by a four-letter type code (ENFP, ISTJ, etc.).
The MBTI instrument sorts for preferences and does not measure trait, ability, or character.