Your question isn't 100% clear to me, but maybe this will help:
In any Microsoft Office application (eg Word), if you go to select a font color, then 'More colors', then 'Custom', you'll see a grid with all the possible colors. Click on it and you'll see a 'swatch' of the chosen color at bottom right.
Then you can read off the number code for that color in the boxes - either in Red/Green/Blue, or in Hue/Saturation/Luminance