|Just double click at the end of the line. That selects the paragraph mark (which is invisible).
Now change the color. That’s all.
Why did I not change the color of the text itself? Because that would be an overkill.
You can learn how to decide WHO can do WHAT with the documents (or other content) which you have shared. If you are using OneDrive for Business, by default, all documents can only be viewed and edited by YOU – and nobody else.
This video contains SPS 2010 screenshots. However, the concepts are still the same as of Feb 2015.