This refers to the way colors are seen. Common color profiles in graphic design are RGB, HEX, CMYK, and GRAYSCALE.
RGB - Red, Green, Blue is the color profile that is supported by screens. When saving images that will be uploaded to a digital display, choose RGB. In the RGB profile spectrum, every color is made of a mixed % of red, green, and blue.
HEX - Hex numbers are special number codes for colors on the web. HEX colors are representations of RGB, but instead of needing to know the percentage of R,G,B in every web color, a 6 digit number code is given to specific numbers like a spot color ink for a print job. See spot color for reference.
CMYK - Cyan, Magenta, Yellow, and BlacK (K) are the primary color of printing. When saving images that will be printed, choose CMYK. In the CMYK profile spectrum, every color is made of a mixed % of these four colors.
Grayscale - Grayscale is black and white and the shades and tints within the black and white gradient spectrum.