The two major color systems used in design are RGB and CMYK. Using the right color systems will ensure that the colors of your artwork will print as intended.
To put it simply:
RGB = Red, Green, Blue. Used for designs displayed on screens. (Smartphones, computers, tablets, etc.)
CMYK = Cyan, Magenta, Yellow, and Key (Black). Used for designs displayed in print. (Magazines, posters, flyers, etc.)