Graphic design programs allow you to design in different color spaces. The RGB color space refers to the primary colors Red, Green and Blue used in computer monitors, video cameras, and televisions. If you are designing images to be viewed in these mediums (like images for a webpage), then working in the RGB color space is fine.
Printers do not use the primary colors in RGB; but rather, they use the primary inks CMYK: Cyan, Magenta, Yellow, and Black (black is abbreviated by the letter K) to reproduce the colors on a printed page.
Because RGB and CMYK color spaces are entirely different, they do not produce the same colors you see. Most graphic design programs allow you to convert the color space from RGB to CMYK and preview the CMYK result on your monitor. If you were to have us convert your colors from RGB to CMYK, we would do a generic conversion that may not be to your liking. By having you do your own conversions, you can control the color result of your printed piece.