Drawing is more personal, as it is a way for the artist to express themselves, while an illustration is more professional and commercial. Illustration is a profession, as publishers and authors often commission them. Drawings can stand alone, whereas illustrations always accompany the text. Renderings are often sketching, or they can be conveyed in two dimensions.
However, you may also use a wide array of tools, including charcoal, colored pencils, pen, and ink. Illustrations are often created as a painting, drawing, or photography. Illustrations are found in books, especially children’s books, and newspapers. Both drawings and illustrations are visual expressions.