Print are typically made on paper, though that's not a requirement. Plate-type prints include etching and drypoint. In drypoint, you cut into a plate, usually a metal, directly using a hard stylus. In etching, you cut into a coating, and the plate is submerged in mild acid. The acid cuts the plate where coating was removed. In both of these printing techniques, you then drive ink into the cuts in the plate, lay paper over it, and pass them through the heavy rollers of a press. This transfers ink to paper. Two qualities of almost all prints are reversal of the image and moving a colored substance to a new surface.
Painting is direct; there is no reversal of image. What you put down is the final form of the image that your viewers will see. There is no transfer, either. You mix your paints and then apply them without intermediary like a plate or stamp. Paintings are made with many different formations of paint. Oil is common, and produces rich effects, though it dries slowly. Acrylic is easier to use. Tempera in the traditional formula uses egg. Watercolors use gum arabic or similar material to hold the pigments in place. The range of paints and their characteristics exceeds the range of inks generally used in prints.
Technically, you can print or paint on just about anything. Practically, that's not so. You can paint on a panel made of wood, and many artist do, but passing a panel through a press could destroy it. Canvas is another support for paintings. You may do certain kinds of printing on canvas, like stamps, but the finer lines of an etching will be lost in the weave of canvas. Paper is the typical print support; almost any paper can be used, from composites that have bits of foliage or other elements embedded in them to clean white sheets.
There are simple ways to distinguish painting from print. First is texture. The print process of pressing obliterates texture, and any texture of ink on the plate will be mashed flat in a print process. Paintings can be flat, but usually have some raised surface. One of the identifying marks of a print is the plate impression -- the indentation from where the plate is pressed into the paper. Paintings can also appear glossy, which isn't characteristic of prints.