How to capture text color in an Office Document

I can think of two solutions off the top of my head:

1: Select the text you want the color of, then click the "More Colors Option" as seen in your screenshot. From there, copy down the "Red, Green, Blue" colors, that will give you an exact match on the color, even if it's a non-standard color.

You can use these three numbers to add color to any element you want, text, boxes, outlines, etc. (see blue circles)

2: The other option, while it only works for text, would be to use the "Format Painter", basically you select the formatting you like, then click the "Format Painter" button, then select the text you want to format. It will copy all the formatting from one section to another. (see red circle)