Click on the highlighter tool. It's the marker icon in the right-center of the toolbar at the top of the window. To change the color of the highlighting tool, click on the downward-pointing arrow to the right of the marker icon and click on the color you prefer for highlighting. The best way to do. The best PDF highlighter app (Mac) comes complete with hefty editing tools that allow you to mark up the PDF however you need; by editing or adding text, inserting images, creating links, or including. Highlight PDF Files with The Best PDF Highlighter App for Mac and Windows.
If you color-code the text in your Word documents, you may feel constrained by the 15 Highlight Color choices:
Fortunately, there's another command available if you want to expand your color palette: Shading. The button is not far from the Highlight Color selector on the Word toolbar: It's just about seven spots to the right over in the Paragraph section:
You can use More Colors to select from the expanded Colors dialog:
Or even enter custom RGB values if you like:

This feature is available in both Word 2007 and Word 2010.

A couple of small cautions: If you use my tip for hiding highlighter marks, any text with Shading will still be displayed and printed. Also, you'll have to remove Shading separately from Highlighting - simply select your target text and choose No Color for each.

Highlighting Tool For Hair
Suzanne