The methods of processing multimedia and graphical information in operating systems are studied using the example of MCI, API and GDI interfaces of Windows operating system. The interfaces of GDI and GDI+ graphics devices are examined in detail. The capabilities and features of the OpenGL graphics library, which is commonly used in the Windows operating system, are presented. The principles of operation of the GDI interface are given. Three types of drawing tools supported by the context of the GDI interface are examined in detail: pen, brush and font. The stages of coordination of logical and physical coordinate systems are considered. The OpenGL library graphics elements (bits arrays, polygons, segments, polylines, etc.), as well as basic geometric objects and a set of polyhedra: cube, cone, torus, octahedron, icosahedron, dodecahedron and tetrahedron are considered. As an example of OpenGL library usage, a three-dimensional graphics editor was studied. It works with three-dimensional objects of various types and allows reproduction of an object in two modes (lines and a solid surface), as well as performance of following operations with a graphic object: deformation, rotation, transpositionong along axes, loading and saving on hard drive.