There are two ways in which computer graphics can be generated on a computer: as vectors or as bitmaps. Bitmapped images consist of a series of tiny squares called pixels, while vector graphics are essentially instructions to a computer to create a series of geometrical shapes each with a given set of attributes. Bitmaps are typical continuous tone images such as photographs. Vectors are typical flat artwork designs such as logos, charts, symbols and illustrations.
Vector images can be generated in a number of programs. Firstly, there are the specialist graphics programs like AutoCad. Then there are general purpose drawing programs such as Adobe Illustrator and CorelDRAW. And, finally, there are any number of non-graphic programs which nevertheless inlude drawing tools. This last category would include all the various programs in Microsoft Office.