Adobe Photoshop is a graphics editing program developed and published by Adobe Systems Incorporated. wikipedia.org

Sketch by Bohemian Coding is a vector creation application for Mac. wikipedia.org

An illustration is a displayed visualization form presented as a drawing, painting, photograph or other work of art that is created to elucidate or dictate sensual information (such as a story, poem or newspaper article) by providing a visual representation graphically. wikipedia.org

Digital painting is an emerging art form in which traditional painting techniques such as watercolor, oils, impasto, etc. are applied using digital tools by means of a computer, a digitizing tablet and stylus, and software. wikipedia.org

Drawing is a form of visual art that makes use of any number of drawing instruments to mark a two-dimensional medium. Instruments used include graphite pencils, pen and ink, inked brushes, wax color pencils, crayons, charcoal, chalk, pastels, various kinds of erasers, markers, styluses, and various metals. wikipedia.org

2D computer graphics is the computer-based generation of digital images mostly from two-dimensional models (such as 2D geometric models, text, and digital images) and by techniques specific to them. wikipedia.org