The surface you paint on is called a support or a substrate. The most common supports are canvas and paper. Canvas is durable, textured, and suitable for acrylics and oils. Paper is cheaper, smoother, and suitable for watercolors and other paints. You can also paint on other supports, such as wood, metal, glass, or fabric. However, you may need to prepare them with a primer or a gesso before painting. There are great painting kits with paints and canvases.