When you click to respond, (reply), to an email some of the text features are not available, (greyed out). Why does that happen?
Outlook is designed, by default, to keep the format of the original email intact when you open to read, print, copy or reply. There is not a way to change that default setting within the program, however, there are third party utilities that can do so. We are not recommending using any third party utility with Outlook as this program can be finicky as it is, never mind introducing another element.
You can manually change the format to HTML. Click on File, Options, Mail and then under Compose Messages you can click the format list and select HTML. All of the text options are now available.