Change Font Color in Report Output

You have 3 options.
A. Change the style definition as mentioned by Nate Decker. Here are the steps to modify the Word template (stylesheet):
1. Go to the folder <jazzteamserverhome>\server\conf\rm\reporting\initialization\templates\word
2. Take a back up copy of printModuleBook.doc (and place it to a different folder. Do not leave it in <jazzteamserverhome>\server\conf\rm\reporting\initialization\templates\word folder.
3. Modify the Word template as per your requirement.
4. Open https://<clmserver>:9443/rm/publish/initialize in browser.
5. After this, you should see your changes in the document generated.

B. Run a Word macro that changes the font color for Headings - DNG can run Word macros once the document generation is complete. Please refer https://rpeactual.com/2014/07/23/use-word-stylesheets-and-run-macros-in-dng/

C. Modify the RPE template (.dta file under <jazzteamserverhome>\server\conf\rm\reporting\initialization\templates\rrdg) that is used for document generation. You can just set red color through Properties->Font->Color. You need RPE (Rational Publishing Engine Studio) for this.

One way to do this would be to change the style definition of the headings in the Word document style sheet. If you are using an out-of-the-box report though, you might want to fork a new version of it to preserve the baseline functionality.