Portrait is a very old art form going back at least to ancient Egypt, where it flourished from about 5,000 years ago.
A painted portrait today is often seen as a luxury, even more than it was in previous centuries. They tend to be painted for special occasions, important people, or simply as artwork. Custom portraits are a special gift.
Sometimes a portrait features an individual, a couple, family, or a large group. Portrait drawing requires the artist to have a mastery over human anatomy