In short, CMYK is used for printing and RGB is used for digital displays.
CMYK (Cyan, Magenta, Yellow, Key/Black) is a colour model used in printing, where it is important to reproduce accurate colors. The CMYK colour model works by mixing different amounts of cyan, magenta, yellow, and black pigment to produce a wide range of colours.
RGB (Red, Green, Blue) is a colour model used in digital displays and computer graphics, including monitors, televisions, and digital cameras. The RGB colour model works by adding different intensities of red, green, and blue light to produce a wide range of colours.